The following steps are shown to repair Windows XP

1. With the help of XP CD boot PC. You want to modify boot order in BIOS so CD boots before hard drive. Verify system records for steps to access BIOS and alter boot order.
2. When "Welcome To Setup" screen appears, you get these choices shown below
This part of Setup program get ready Microsoft Windows XP to run on PC:

To setup Windows XP now, press ENTER.

To repair a Windows XP installation using Recovery Console, press R.

To exit Setup without installing Windows XP, press F3.
3. Press Enter to start the Windows Setup.
To Repair Install press Enter.

4. Allow License Agreement and Windows will look for current Windows installations.

5. Choose installation you would like to repair and press R. If you don’t want to repair then END setup.

6. Setup will copy needed files to hard disk and restart. Do not press any key to start from CD when message shows. Setup will go on as if it was doing a clean install, but your applications and settings will stay undamaged.

7. Again do updates as first Windows XP installation. Repair Install using a new pre service pack 1 or 2 XP CD utilized as install media will eliminate SP1/SP2 correspondingly and service packs plus updates issued after service packs want to be reapplied.