What kind of post beeps do you get? Have you tried to boot from your Win XP CD? Have you tried to do a repair install with your Win XP CD? If you need help with repairing Win XP let us know. There is an excellent post on this board on how to do it.
If you can not boot from your Windows XP CD, there is something fundamentally wrong, because you will have eliminated your Hard Drive and OS on that HD.