It could be although unlikely that your restore points have been corrupted. Try doing a repair installation of XP, before you do (if you choose to that is) make sure you back up your documents and essential files.
usually when you restore don't work, it's because you added new hardware and that throws it off
The Ultimate Hard Drive Utility PowerMax 4.23. (It now has the ability to clean a Boot Sector virus on the quick erase option.)
The best browser Netscape 8
Have you accidently delete something? Look here (trial. the better one) and here(free)