When you first start up the computer you will see a message that says to press a certain key to enter setup. It is usally an Fkey or esc or del. Pay attention as this message may flash very quickly. Tap that key as the computer starts op.
This will take you into BIOS. Here you want to look for Boot order or Boot sequence or maybe even just Boot. You want to set your CD drive as the first boot device. You usually press the plus and minus keys to move your devices up and down in the boot order. Once you have your CD drive set as the first boot device you want to insert your XP disk into the CD drive. Now exit setup and SAVE CHANGES (F10).
The computer will reboot. You may see a message that says: "Press any key to boot to CD". If you do just keep tapping a key as the computer starts. You should hear the disk start spinning in the drive and then see a blue screen with the words XP setup near the top. It will load a bunch of files and then you should see this screen:
Press R to load the recovery console. Then follow the steps from here:
http://icrontic.com/articles/repair_windows_xp
