shutdown, but instead restarts?

[nerve]

I have installed a fresh copy of Windows XP Pro on my machine. All runs correctly, however when I shut down my computer, it instead restarts quickly after it shuts down. I have no idea why it is doing this, and it is very aggrivating so I must shut down manually. Does anyone else have this problem? is it driver/hardware problems? I get no error messages when I shut down either, it just automatically restarts with no errors/problems. Help is appreciated.

[XJnine]

Here's some info from Microsoft:

http://www.microsoft.com/windowsxp/using/helpandsupport/learnmore/russel_02may13.mspx