Had one on work computer that IT had issues with for a few months. It kept reintalling itself. Not sure what it was though. They finally figured it out. Had to do some IE options changes among other things i dont remember seeing.
The Windows Xp Security virus comes to mind first. It has infected a few clients and family members computers that most of which I wasnt able to do a reinstall due to lack of the backups being done and not having Xp media center edition...
it will restart after you exit the bios after changes are made or not. But yes it does apply the changes upon exiting the bios and does do a restart.
now if it is doing a restart every time you start computer WITHOUT you entering bios...