Make sur your computer is configured to start from the CD drive. Put the XP CD in & restart the computer When press any key to boot from CD is displayed Press enter.When you see To Set up Windows XP now, press enter. You will then see an option to press R to enter the recovery console DO NOT SELECT this option, on the Windows licensing agreement make sure that your current installation of Windows XP is selected in the box, & then press the R key to repair XP. Follow the instructions on the screen to complete the set up. If you have XP Service Pack 1 you will lose it & will need to reinstall that afterwards. Good luck.