If I hit the reset button.. or choose restart from window. The monitor shuts down. I can't tell that anything else is happening. I did note the mouse didn't come on or the keyboard.
I looked over cmos and i have to be the first one to say I don't understand all the settings there. I may have something set wrong but i wouldn't have a clue what. I changed graphics cards and i'm using and old nvidia 6600. doesn't pull as much as some of the new cards. The computer was working fine till i re-installed windows xp so I don't think its a button problem. The graphics card in an nvidia and the drivers came straight from their board.
You reinstalled Windows XP, and,
You installed a different graphics card. This would sound like a driver issue with the mouse and keyboard involved now.
Did you ever clear CMOS?
Do that, and if that doesn't fix it;
click Start, right click on My Computer, click Manage, click Device Manager, click the + by Display Adapter, right click on the card shown, click uninstall, reboot.