IT record material

TASK NO: 1

AIM: Introduction of computers and identifying the peripherals   of computer.

Computer is defined as an electronic device which takes the instructions given by the user as input and gives the result as output in user desired format. The father of computer is Mr. Charles Babbage.

Computer Generations:

1^st Generation    :        Made with vacuum Tubes

2^nd Generation   :       Made with Semi-Conductor devices Diodes& Transistors

3^rd Generation   :       Made with I.C. (Integrated Circuit)

4^th Generation   :       Made with VLSI (Very Large Scale Integrated Circuit)

5^th Generation    :       Used A.I. (Artificial Intelligence) Technology

Computer can be divided into 4 major parts.

1.    Hardware

2.    Software

3.    Data or Information

4.    Users

Hardware:  The parts which we can see physically with the computer are called as hardware parts of computer. Problems related these parts are Hardware problems. Finding these problems and rectifying is called Hardware troubleshooting.

E.g.: Monitor, Key board, mouse, CPU etc.

Software: Software is interface between the Hardware and the User. Set of instructions can be called as a program. Set of programs can be called as a Software package. There are various types of software we have in the computer world.

E.g.: Operating system software packages, Programming Language software and Application software packages.

Data:  The information passing through the system and the user to get the required output is called Data.

E.g.: The input information given to the system and the output information taken from the system.

Users: The persons or machines, which are using the computers, are called as Users.

Block Diagram of Computer

Basic Operation of the Computer:

The above diagram shows the Block diagram of computer. According to the diagram basically the computer will take the instructions given by the user through the input device to memory unit. Memory unit will collect required information or data and sends to the central processing unit CPU)’s control unit for the processing the instruction. In CPU, control unit will take care of controlling the flow of instructions and Arithmetic and Logic Unit (ALU) will take care of processing the instruction. Finally the result will send to the memory and to the user.

Input devices:

Input defined as:

•         Data from the user to the computer

•         Converts raw data into electronic form

The following are the list of input devices:

• Keyboard
• Pointing devices

Ø      Mouse

Ø      Track ball

Ø      Touch pad

Ø      Pointing stick

Ø      Joystick

• Touch screen
• Graphics tablet
• Stylus
• MICR
• OR
• SR
• Digital camera
• Scanners

Brief description about the input devices:

Keyboard:

•         Traditional

–        Looks like typewriter with extra keys

•         Non-traditional

–        Fast food restaurants

–        Each key represents a food item rather than a character.

Mainly 5 categories of keys are there. They are

                  Functional keys( F1 to F12 )

                  Cursor movement keys

                  Alphabetical keys( A to Z )

                  Numerical keys( 0 to 9 )

                  Special keys (tab, caps lock, shift, space bar, enter…)

Mouse:

•         Types

–        Mechanical

–        Optical

–        Wireless

•         Features

–        Palm-sized

–        1 or 2 buttons

–        Wheel

Track ball:

–        Upside-down mouse

–        Ball on top

–        Roll ball with hand

–        Laptop computers

Touch pad:

–        Pressure-sensitive pad

–        Cursor moves as you slide your finger

–        Laptop computers

Pointing stick:

•         Pressure-sensitive post

•         Mounted between G and H keys on keyboard

•         Apply pressure in a direction to move cursor

Joystick:

•         Short lever, Handgrip

•         Distance and speed of movement control pointer position

Graphics tablet:

•         Digitizing tablet, Rectangular board

•         Invisible grid of electronic dots, Write with stylus or puck

•         Sends locations of electronic dots as stylus moves over them

•         Creates precise drawings, Architects and engineers

Touch screen:

–        Self-help stations

–        Easy to use

–        Where found

•         Malls

•         Disney World

•         Government offices

Stylus:

–        Pointer

–        Handwritten input

MICR (Magnetic-Ink Character Recognition):

•         Read characters made of magnetic particles

•         Numbers on the bottom of checks

•         MICR inscriber – adds characters to check that show amount cashed.

OR (Optical Recognition):

•         Optical mark recognition (OMR)

–        Mark sensing

–        Exams

–        Recognizes the location of the marks

•         Optical character recognition (OCR)

–        Light source reads special characters

–        OCR-A is ANSI standard typeface for optical characters

SR (Speech Recognition):

•         Speech recognition devices

–        Input via a microphone

–        Voice converted to binary code

•         Problems

–        Speaker-dependent

–        Voice training

Digital camera:

•         Photos stored in electronic form

•         No film

•         Point, shoot and Edit

Scanners:

Scanners convert hard copy into soft copy. Mainly 3 types of scanners are there:

•         Handheld

–        Least expensive, Least accurate

–        Portable, Wide document causes problems

–        User must move the scanner in a straight line at a fixed rate

•         Flatbed

–        One sheet at a time

–        Scans bound documents

•         Sheet feed

–        Motorized rollers

–        Sheet moves across scanning head

–        Small, convenient size

–        Less versatile than flatbed

–        Prone to errors

Output devices:

•         Information for the user

•         Types

–        Printers

–        Speakers

–        Monitor

Printers:

•         Produces information on paper

•         Orientation

–        Portrait and Landscape

•         Methods of printing

–        Impact and Non impact

Impact printers:

Line printer:

–        One line at a time

–        High volume

–        Low quality

Dot-matrix printer

–        One character at a time

Non impact printers:

Laser printer:

•         Transfers images to paper using a light beam

•         Prints one page at a time

•         600-1200 dpi – High quality

•         Speed

–        Personal laser printers:  8-10 ppm

–        Network laser printers:  35-50 ppm

–        High-volume laser printers:  up to 1000 ppm

•         Black and white / color

Ink jet printer:

•         Spray ink at paper

•         Black and white / color

•         Excellent graphics

•         Good quality

•         Slower than laser

Non impact printers Choose based upon:

•         Speed

•         Quality

•         Black and white vs. color

•         Price

Speakers:

By using speakers we hear the voice signals. These are used in

•         Automobiles

•         Telephone surveys

•         Catalog order is ready

•         Your payment is late reminder

Monitor:

•         Data that is entered appears on the screen

•         Screen is part of the monitor

Mainly 3 types of monitors are there. They are:

1) CRT

Color vs. Monochrome

•         Color

–        Typical monitor sold today

•         Monochrome

–        Green or amber on a contrasting background

–        Less expensive than color

2) LCD

•         Liquid Crystal Display (LCD)

•         Primarily on laptops

•         Moving to desktop

•         Skinny (depth) regardless of size

3) LED

Computer hardware peripherals:

External parts:

      Monitor

      Keyboard

      Mouse

      Cabinet

Internal parts:

      Mother board

      Socket 478

      Processor

      CPU heat sink and fan     

      Fan connector

      North Bridge

      South bridge

      RAM slots (SD-RAM, DDR-RAM)

      AGP slot

      PCI slots

      CNR slots

      BIOS

      CMOS battery

      Different ports

      Different screws

      ATX Power connector

      Floppy drive connector

      Primary and secondary

      Hard disk drive

      Floppy disk drive

      CD-ROM

      CD writer

      SMPS (Switching Mode Power Supply)

      Powering LEDs and cables

      buses

       

       

TASK NO: 2

AIM: Personal computer Assembling and Disassembling.

Steps to be followed in Personal computer Disassembling:

1.    Disconnect all the external parts and cables of CPU Box or Cabinet.

2.    Remove the Cabinet.

3.    Observe the inside parts how their screws and cables are connected and draw the internal lay out of CPU.

4.    Disconnect all the power cables connected to the storage devices.

5.    Disconnect all the data/communication cables connected in between storage devices and mother board.

6.    Disconnect Front panel connections like speaker, power LED, power switch, Reset switch and HDD Led cables connected to the mother board.

7.    Remove the switched mode power supply (SMPS) connected to mother board.

8.    Remove the storage devices like Hard disk, floppy disk drive and CD-ROM drive.

9.    Check any External/IO Cards connected to the motherboard PCI slots. If any card is observed, first we have to remove it and then remove the motherboard from the cabinet carefully.

10.          Check all the devices list with no. of screws and keep in proper order for assembling

Precautions to be followed in assembling:

·        Do not touch the circuits and other parts of mother board

·        Remove the mother board carefully and keep in neat place

·        Keep all the parts aside carefully in proper place

·        Keep the components away from moisture

·        Avoid Using pressure while Assembling or Disassembling

·        See that there are no cable mixed with the internal fans after assembling

Steps to be followed in Personal computer assembling:

1.    Re-fix all the parts in the order we removed.

2.    Fix mother board carefully which is having processor and RAM already fixed on it.

3.    Connect any external cards and give the SMPS power supply to the mother board.

4.    Fix the SMPS (Switched mode power supply)

5.    Reconnect all the Front panel connections like speaker, power LED, power switch, Reset switch and HDD Led cables connected to the mother board.

6.    Fix all the storage devices like Hard disk, Floppy Disk Drive and CD-ROM drive.

7.    Fix the power and data cables to the storage devices.

8.    Check all the devices once according to your list prepared by you while disassembling.

9.    Fix the cabinet properly.

10.                      Reconnect the external cables related to the monitor, keyboard, mouse, power supply.

Task No: 3

AIM:   Installation of Windows XP operating system

Before installing the windows XP operating system installation the below steps should be followed and checked.

1. Hard Disk Configuration settings: We should define the master and slave before starting installation process. The storage devices connecting to the IDE slots should be defined as master and slave. According to the settings we have on the hard disk the jumper pin should be connected to the device to make it as master or slave if we have multiple disks. Master disk will be used to boot the system whereas slave disk is used for additional storage.
1. The devices connected to IDE1 are treated as primary devices (We can connect maximum two storage devices to on IDE slot, based on the jumper settings master and slave will be configured)
2. The devices connected to IDE2 are treated as secondary devices (We can connect maximum two storage devices to on IDE slot, based on the jumper settings master and slave will be configured)
2. BIOS (Basic Input Output System/Software) or CMOS settings: These settings should be checked before starting the installation process to know the booting priority. This software is stored in the Flash Memory Chip (CMOS memory) we have on the motherboard.

Generally by pressing DEL button or F12 button on the keyboard before starting Operating system loading we will see the CMOS setup or BIOS setup screen. There one can do the settings like Date and Time and storage device priority settings.

3. File Systems: The storage devices should be formatted (dividing into small memory areas) using some method of file systems based on the compatibility of the operating systems. There are three important methods of file systems we have in windows based operating systems.
1. FAT16 (File Allocation Table 16-bit): This method of file system is introduced first in MSDOS in 1981. It is widely used file system for floppy disks. Later on FAT16 was updated due to its disadvantages. They are :

                                                              i.            No file security

                                                             ii.            File compression and encryption is not possible

                                                           iii.            It has fixed number of clusters(Cluster is the minimum size or space or area occupies when we add a file to the disk)

2. FAT32 (File Allocation Table 32-bit): The updated version of FAT16 is FAT32. This was introduced with windows-95 OS. There are some advantages we have with FAT32 compared to FAT16.

                                                              i.            The number of clusters are increased in FAT32

All other disadvantages we had with FAT16 are applicable to FAT32 also.

3. NTFS (New Technology File Systems) :  This is the file system now a days the people are using to format the hard disk for windows OS. This is introduced with windows NT OS. Here all the disadvantages we had with FAT file systems are rectified. There are some important advantages  in using NTFS are:

                                                              i.            Cluster division is updatable according to the size or partition of the Hard disk.

                                                             ii.            File compression and encryption is possible

                                                           iii.            Very much secured file system

4. Partitions: Before formatting the Hard disk, the partitioning should be done based on the requirement. Partitioning is just dividing the hard disk logically into various sizes. The first or root partition is treated as primary partition and the rest of the partition is extended partition.

The below steps gives the installation of Windows-XP OS process:

1. Switch on the system and check the working condition and prerequisites to load the XP operating system.
2. Press Del/F12 button to go to CMOS/BIOS setup
1. Check Date and time
2. Check all the storage devices are detected or not
3. Check the booting priority ( First priority should be given to CDROM)
4. Save all the settings and come out of CMOS setup
3. Insert the operating system CD and Press any key when it is prompted to start the system with XP setup.
4. Follow the steps
5. In the partitions screen it shows the existing partitions, If we want to continue with the existing partitions just select the partition to install the OS else we can create our own partitions by deleting all the existing partitions.( Note: Be care full while deleting the partitions because the existing data will be lost).
6. This screen will ask the selected partition to format using any method of file system before continuing installation. (Use NTFS for better usage).
7. The setup will format the partition and copies all the OS files from CD to the selected partition on the hard disk.
8. The system will restart automatically this time you do not press the key when it is prompted.
9. Just follow the steps accordingly to finish the installation like Date/time, Language, Country, System name, Company details and finally user names details.
10. The setup program automatically installs all the devices in our system. After completing installation it will restart, you remove the OS CD from CDROM drive

Task No: 4

AIM:  Installation of Linux operating system on already Windows XP loaded system.

DEFINITION OF OPERATING SYSTEM:

Operating system is one, which helps to have an interaction between user and hardware of the computer.

Dual Booting: Installing more than one operating system in a computer is called dual or multi operating system. Loading all related operating system files from both the operating systems into the system main memory according to the user selection is called “Dual booting”.

 Linux is open source operating system software. It is designed by Linus Thorvaldsen a student of Helsinki University, Finland. User can change the Operating system according to his requirement.

Drive naming specification in Linux:

·        Primary master            -                       /dev/hda

·        Primary slave              -                       /dev/hdb

·        Secondary master       -                       /dev/hdc

·        Secondary slave          -                       /dev/hdd

This is meant for IDE based hard disks.

Various partitions in these will be specified as below:

·        Primary partitions       -       /dev/hda1, /dev/hda2, /dev/hda3, /dev/hda4 (Numbers 1-4)

·        Extended partitions     -     /dev/hda5, /dev/hda6 etc (Number 5 onwards)

·        Floppy disk drive A      -     /dev/fd0

·        Floppy disk drive B      -    /dev/fd1

File systems used in Linux:

Minix:  It is the first method of file system used in Linux. It is preferable for boot and rescue disks.

EXT2:   It is introduced in 1993.It is designed to make easier for new features to be added so that it can constantly evolve into a better file system. It handles up to 4TB size and supports long file naming (1012 characters).

EXT3: It is introduced in REDHAT Linux 7.2 version. It has very good compatibility feature with ext2 .The backward compatibility enables to run kernels that are only EXT2 aware with EXT3 partitions.

Mounting: is deciding which part of the Linux directory tree should be located on each partition.

Mount Point: It refers to the directory you associate with a disk partition.

Swap Partition: When the OS runs out of physical memory (RAM), it can move or swap the contents of currently unneeded parts of RAM to make room for a program that needs more memory. This SWAP memory is called virtual memory. This process of swapping data back and forth between the RAM and the disk is also known as “Paging”.

Boot Loader: It is a program that resides on our hard disk and starts REDHAT Linux from the hard disk. Boot loader will be in one of below two locations.

·        MBR (Master Boot Record) It is the first sector of the hard disk.

·        First sector of partition where you have loaded Linux.

There are two types of Boot loader programs in general in Linux:

·        LILO (Linux Loader): This type of Boot loader program is used before the RHL 7.2 version.

·        GRUB (Grand Unified Boot Loader): This is used from the 7.2 version. It will write in the MBR.

The below steps gives the installation of Linux OS process where the XP is already loaded:

1. Switch on the system and check the working condition and prerequisites to load the Linux operating system.
2. Press Del/F12 button to go to CMOS/BIOS setup

1. Check Date and time
2. Check all the storage devices are detected or not
3. Check the booting priority ( First priority should be given to CDROM)
4. Save all the settings and come out of CMOS setup

3. Insert the operating system CD and Press Enter key when it is prompted to start the system with Red hat Linux installation.
4. Follow the steps
5. In the disk partitions screen select manual partitioning option, it shows the existing partitions, If we want to continue with the existing partitions just select the partition to install the OS else we can create our own partitions by deleting all the existing partitions except the XP partitions.( Note: Be care full while deleting the partitions because the existing data will be lost).
6. After making proper free space, create minimum three partitions Like Boot (100mb size) , Swap(give double the RAM size) and root(/) partition which is required for Linux installation. Select file system as EXT3 for the root partition.
7. Follow the steps (Just say next).
8. The setup will format the partition and copies all the OS files from CD to the selected partition on the hard disk.
9. Just follow the steps accordingly to finish the installation like Date/time, Language, Country, System name, Company details and finally user names details.
10. The setup program automatically installs all the devices in our system. After completing installation it will restart, you remove the OS CD from CDROM drive

Task No: 5

AIM: Hardware Trouble shooting

All the problems related to the hardware parts are called hardware problems. Finding these hardware problems and rectifying them is called troubleshooting.

Keyboard related problems:

          If there is any problem in the keyboard detection

·         Disconnect the keyboard

·         Check all the pins and reconnect it to the port

·         It may be detected

·         If not detected, restart the system after reconnecting.

·         If it is detected, then the problem lies in the keyboard.

Problems related to mouse:

The same procedure is to be followed for the mouse. Initially the mouse must be disconnected and the system should be restarted by connecting another mouse to it. Before this step check the pins and reconnect. If it is not detected perform the later task.

Power supply problems:

          The power supply problems are mainly due to 3 reasons.

1.     problems regarding SMPS

2.     problems regarding AC power switch

3.     Problems regarding the front panel connections.

If any power supply problems occur then the following steps can be followed.

ü      Check whether the AC power cable is properly connected or not.

ü      Check the SMPS power cable is to be connected to the motherboard properly or not.

ü      Check the power switch cable of the front panel connections

ü      If it is ok, then check with other SMPS.

Problems due to front panel connections:

Problems in front panel may be in—

LED

If the led is not glowing, then check the connections of the Led according to the pin diagram and recheck (HDD, POWER).

RESET

If the problem is with reset switch then check the connection of the reset switch to front panel.

SPEAKER

If the speaker is not working then recheck all the connections of the speaker, according to the pin diagram in front panel.

Details of the beeps occurred in the POST (Power On Self Test) operation.

Single Beepà it indicates that everything is normal and post is success.

Two Beepsà it indicates post or CMOS error. CMOS error is due to battery or corruption of program.

One long Beep and one short beepà it indicates motherboard problem.

One long beep and two short beepsà Display related problem is indicated.

Three long beepsà it indicates keyboard related error or problems.

Continuous long beeps à it indicates Ram is not working properly.

No beeps à It indicates the absence of power or presence of a Bad CPU (processor)/motherboard.

Problems related to RAM:

If repeated continuous long beeps are produced with POST then the problem  is related to RAM connected in the RAM slot.

• Open the cabinet
• Disconnect the RAM and connect it again properly.
• If the problem persists put the RAM in another slot & check.

Processor Problems

 If there are any problems with the processor, the system will not respond. So check all the connections of processor and RAM.

Adding additional hard disk to the system

The steps to be followed are:-

·         open the cabinet

·         Add the additional hard disk to the IDE1, or IDE2. If the jumper is present to the additional hard disk, remove it to make it a slave.

·         Give the power connections from SMPS, connect the data cables properly.

·         Now start the system and copy the files from requires partitions (drive) to the first hard disk.

·         Switch off.

·         Open the cabinet and remove the earlier connections made to the additional hard disk.

Adding additional cd-drive or cd writer

The steps to be followed are:-

1.     firstly, open the cabinet

2.     add the additional cd drive or cd-writer.

3.     Connect the data cables and power connections from SMPS.

4.     now start the system and copy the files from required drive to the first cd/hard disk.

5.     switch off.

6.     open the cabinet and remove the earlier connections made to the cd drive.

Adding additional hardware cards:

After getting the required card, connect it to the PCI or IO slots or external slot. Restart the system and if the software is needed, load the new software concerned to it.

Making the CMOS setup values to the default settings

If you want to make the CMOS setup values to the default/you have forgotten, then remove the CMOS battery and connect it again. Then, this makes the CMOS setup values to the default setting. This procedure is not applicable for all mother boards.

Booting Problems:

          If there is any system startup problem, go to CMOS setupà Advanced setup to check the booting priority.

Still if the problem is not solved; check the storage devices you have in the system.

Problems related to display:

1. Check whether the monitor power cables are properly connected or not.
2. If it is ok, then check the monitor cable connected to CPU(15 pins)
3. if it is not solved, then the problem is with VGA card(Video Graphic Adapter).

Spots and discoloration:

This is due to the magnetic field developed around the monitor.

Steps to avoid this are:-

1. Avoid turning of monitor
2. check the presence of magnet near the monitor
3. do these steps after checking the power cables.
4. if strong magnets are present, they may damage the monitor permanently.

Noise by monitor

The usual buzzing or clicking sound occurs due to the voltage changes. This is ok. But, if it makes much noise even when the refresh /resolutions are not changed, when the problem is with monitor.

Cd-drive related problems

1. Check the audio interface cable. if your replaced your cd-drive and it suddenly will not play music or your PC was never able to play music, then this is the problem. This cable runs between the cd-drive and either the motherboard or sound card without it, you will have no audio running out of your cd-drive.

2. Check the speakers make sure the speakers are hooked up correctly and are powered on.

3. make sure your computer has a sound card in it. Without this crucial device, you will never be able to play music in the computer.

These are some problems generally occurs while using the computers.

Task No: 6

AIM: Software Trouble shooting

Set of instructions can be called program. set of programs is called software package. The problems related to the software are called as software problems. Finding or identifying these problems and rectifying them is called software trouble shooting. Software can be divided into

·                                       Operating system software: E.g.: Windows Xp, Linux.

·                                       Programming language software : E.g: c, c++, java, Visual Basic, Visual c++

·                                       Application software  E.g: Ms.office.

·         tools E.g: Audio Player software

Problems in the installation of operating system:

          When you get “file cannot be read” error in the middle of installation of any software, the system will ask you to retry the installation with other good CD or you can skip the respective file. The installation continues automatically. No need to start from the beginning.

Adding the required software to your system after installing the operating system.

Suppose, if you want to load ms office, follow the following procedure.

Installing MS Office

1.     Insert the ms office CD in the CDROM.

2.     Open CD drive in the my computer

3.     Check for installation of the executable file (the name may be generally setup.exe or install.exe)

4.     Enter the product key when asked. E.g: GWH28-DGCMP-P6RC4-6J4MT-3HFDY

5.     Provide the information like username, organization details and click next>>

6.     Accept the license agreement and click Next>>

7.     Select the type of installation among below

1.     typical installation(recommended)

2.     complete installation

3.     minimal installation

4.     custom installation

8.     Select the drive and folder to install the software.

9.     Continue the installation

10.         After installation we can get below message.

“Microsoft installation is successfully completed”

Removing the software

          To remove particular software the following steps should be followed.

1.     Go to control panel

2.     Click on Add/Remove programs

3.     Click on remove the required file or software.

Repairing the Windows Xp operating System:-

Sometimes windows Xp operating system could not be accessed due to corruption of files or missing files. This may happen even due to the virus. At such times there is no need to install windows again in the system. The whole operating system can be repaired. At the time of reinstallation select the option Repair instead of install. The missing files or the corrupted files are automatically copied and the remaining operating system programs are left unaffected or reinstalled.

Reinstalling the operating system without loosing the existing data in the system.

          For instance, in the existing system you have 3 partitions namely C,D,E and if you have any problem with the existing operating system and you want to keep all the existing data in all drives as it is , without deleting, then the following steps are to be followed.

1. Insert the operating system CD in the CDROM, start the system

2. In the partitions screen, don’t delete the existing partitions select the required partition to load operating system (mostly CD Drive)

3. Select and start the installation in that, select the formatting method “leave the current file system as it is (no changes)”

We can windows is installed without losing the previous information.

Failure of software installation

Ø      Reboot or retry

Ø      Check the event log

It can be found out using control panel and double clicking administrative tools.

Check the install log.

ü      Make sure your system is up to date.

ü      Clear your temporary file folder

ü      Disable your antivirus program

ü      Follow the prerequisites.

Problems when trying to run old software

1.     Performance: your computer speed can be severely degraded by installing and running old software.

2.    System files:  by installing older software on your PC, you may be overwriting important files with older versions.

3.    Memory leaks: old software can potentially be a severe of memory leaks. This in turn causes your computer to crash intermittently.

Installing Windows optional Components

1.     Open windows control panel

2.     Double click Add/Remove programs

3.     Click off any components you want to install (or uninstall) and click next.

Uninstalling Software

1.     Open windows control panel

2.     Double click Add/Remove programs

3.     select a Program which need to uninstall

4.     Click on remove button

5.     click on yes while system asks for conformation to uninstall

6.     Now uninstall process will start.

Updating Windows automatically:

Windows Xp

1.     Right click my computer on desktop

2.     click properties

3.     click the automatic updates Tab

Windows 2000

1.     Click start.

2.     Point to setting

3.     Click control panel

4.     Double click the automatic updates applet.

Updating Microsoft Office 2003

1.     Open up any of the office suite of programs.

2.     Click help on the top toolbar

3.     Click check for updates

4.     Click scan for updates

5.     Click start installation

Preventing on self from deleting critical system files

1.     Right click start

2.     Click explore

3.     Click tools in the upper menu

4.     Click folder options

5.     Check “Hide protected operating system files”

6.     Check “do not show hidden files and folders”

7.     Uncheck “display the contains of system folders”

8.     Click ok

After deleting replacing a critical system file

1.     Check the recycle bin

2.     Use the system file checker utility. To run the SFC click startà run and type SFC /SCANNOW and then click ok.

3.     Use systems restore

4.     Install the latest service pack. A service pack is a collection of system files that are used to replace existing system files to solve existing issues. Installing the latest service pack will usually reinstall any missing or corrupt.

Use windows update: The file you deleted may be part of a windows hot fix or critical update.