Not Powering Off

I just picked up a new PC to me. It was running W98SE when I got it. Was told that the problem that when you poweroff the PC that it restarts, and you need to poweroff again before Windows starts was a W98 bug.
It is now running W2000 and the problem remains. I change the reg setting to poweroff at shutdown. Now I just have a choice b/w restart and restart.
The bios is an Award bios and I have tried to disable any of the power mgmnt settings that may be causing the problem.
I am not sure where the problem lies.