PC won't turn off

Just installed Biostar M7NCD, Athlon XP 3200+ and 1Gb of Corsair ddr400. OS is XP Pro. When I click the "Turn Off" button my PC reboots. Can only turn PC off by manually shutting power off. Changing power management drivers didn't help. Changed BIOS power setting without success. Very frustrating indeed. Any advice greatly appreciated.
Walt

 

http://support.microsoft.com/default.aspx?scid=kb;en-us;311806 what this page is saying is that maybe youre getting an error during startup, but it posts too fast to notice, and your computer is set to automatically restart after a system failure. but who knows if thisis the case

 

Thanks a million for the tip. I'm on the trail. So far it looks like the nVidia agp pci bridge driver is the culprit however a list of errors appears some of which are not listed with MS or don't seem relevant. (Example: the root cause is listed as a problem with Roxio. I don't have Roxio on my sytem.)
Have a great day.
Walt