I wiped my hard drive completely, including the OS which is XP. I have an xp disk to put back on, but everytime i boot from CD it gives me the error disk boot failure and i have no idea what to do. any help would be appreciated thanks
I assume you have placed the XP Install disk in the optical drive BEFORE turning it on. If it fails to read that disk properly, two possibilities: the disk is faulty, or the drive has a problem.
A faulty disk could have many causes, but one simple one MIGHT be it's just dirty. You could try wiping it GENTLY with a damp cotton cloth, then drying gently and letting it get completely dry. You want to avoid any scratching. If you can, verify the disk's condition by putting it into another machine and seeing if it will boot from that disk. If the disk still cannot be read successfully in a second machine, you have to suspect it has problems.
The optical drive unit could have a problem. Check that all its power and data cable connections are securely plugged in. In fact, try unplugging and re-connecting them to be sure. Then get an optical drive cleaner and use it in case there is a dust build-up inside. These tools often are a combination of a drive cleaner and a test disk with tracks to check audio track left-right assignment, etc. Again, see if you can get some other optical disk, preferably a bootable Install disk or something, just to verify that the optical drive can handle a known-good disk.