OT: What is the best way to restore crashed xp

[joe at actionline.com]

Much as I despise widows and everything M$, for the same reasons that one
should avoid selling one's brother-in-law a used car, I am resisting the
urge to try to convert my nephew to Linux for now.

Instead, I just need to find a fast and efficient way to get his win-xp
box restored to a working state ... and I do not have an xp disk and key
available to reinstall.

So, surely would appreciate any guidance from the plug brain trust on this.
I wasted 4 hours yesterday using the HP restore function and when that was
done I could not get the control panel to display so I could delete a lot
of stuff that I suspect is causing the system to run incredibly slow and
continually self-reboot.

Help!