When I turnoff Windows XP, it goes thru the process of turning off but INMEDIATELY reboots itself, so the only way I can turn off my computer is to pull the plug literally. This is most annoying. Anybody has and idea of why this is happening? It just started a few days ago.

   You need to make sure that it does not say Restart in the window that appears when you click on the Shut Down button.  You need to select Shut down in that window and then click on the OK button.
   An alternative to pulling the plug is to hold in on the On/Off button for five seconds.  Be sure you only do this after Windows has said that it is OK to shut down your computer (or once the computer begins restarting).

The alternative solution works, thanks. But the original problem still there, as soon as it turnsoff it restarts I made sure that I don't push resttart.