You can boot to the XP cd and when you see the Welcome to setup press the letter RYou will get a dos promptThen type 'chkdsk /p' without the quotes and hit enterWhen that is done type 'fixboot' and hit enter'Y' and enter at the promptThen type 'exit' and hit enterThe system will now reboot into WindowsIf for some reason that don't work for you, you can boot to the recovery console like above and.Type 'chkdsk /r' then enterWhen done type 'exit' and hit enter.This will take longer, but the system should boot back into Windows. When you turn the computer on, keep tapping del or pf1 or esc or some key that will get you to the BIOS.find boot sequence in the BIOSselect 'cd rom first' then whateversave your settings and exit BIOSyou should have put the xp-cd in the cd rom drive first.it will boot up from cd. When it sees that you already have the operating system on the hard disk, it will start the repair installation.another way would be to save all your data by taking the hard drive out of that machine, installing it as a slave drive in another machine, saving the data somewhere else, taking it back out, re-installing it, and doing a clean windows install. You have to format the hard drive before you do this.