If system restore will not restore on any of the points already made. Open System Restore click on System Restore Settings/Turn System Restore Off/ reboot, and turn System restore back on, it should make a new restore point that will work. Test it.
(you will lose all previous restore points, but since none work you have nothing to lose). If by any cahnce that doesn't work, System Restore can be repaired using a system file scan.go to Start/Run/type sfc /scannow (Watch the space between sfc and /) hit enter. You will need your XP CD.
I don't know why your computer had a serious error report, it could be one of many things. Try and fix Sysatem Restore first.