XP STILL restarts when i shut down

My girlfriend has windows XP on her computer. At first she had no problem shutting it down. Then after i installed some new drives, a printer, etc. it started doing that thing where it restarts when i go to shut down. I looked at microsoft's website and on here and all i got was to uninstall Roxio (which isnt even installed) and to disable "automatically restart" which i did. I tried shutting it down after this and still had the same problem. I havent gotten it to shut down at all since then, but I just (like 60 seconds ago) found out that she got it to shut down right for once. So the problem might be fixed now, but if it isnt, does anyone have any other ideas?

Either one or both of the following articles may be of some help to you...

Resources to Help Troubleshoot Shutdown Problems in Windows XP:

Windows XP Shutdown & Restart

sorry to take so long but i did try both of those, and neither have fixed the problem. For about a month or so it pretty much shut down right every time. She doesnt have any viruses or spyware (i have checked that personally), but it started doing it again. It almost does it randomly now but probably 80% of the time, it wont shut down right. Does anyone know of any other settings that could be changed or any programs that might have been installed and causing the problem?

This sounds like a power management thing. Try turning off power management in windows and in the bios. See if that helps.