system restore failure

[ken]

have continually attempted to reset my Windows XP Pro to a
previous setting. Click on the appropriate restore point
in system restore and it appears the program is working to
the point where the computer reboots. Then, I get a mess
age that system restore didn't restore the computer to a
previous setting. I have tried various restore points with
the same result. I have turned off my XP firewall to see
if that might be a problem Same result. Any help will be
aprreciated.