CPU usage 100% help!

[imported_bsemaiktehr]

My computer (specs in my signature) is behaving very oddly. I noticed a drop in performance recently while playing one of my games (AoE3), so I minimized and brought up task manager to see what was causing the problem. The CPU usage had spiked to 100% and was stuck there. When I right-clicked on the taskbar tab for the game, the usage went back down to 0% while the right-click menu was open. However, the usage goes right back up when I close the menu (weird).

This happens on all of my games. I built this computer in late April, and this is the first problem I have had with it. Any graphics-intensive program (any game, iTunes with visualization on, google earth on high resolution...) makes the CPU usage spike to 100% and it stays there until I close the app. This is only happening with graphics-intensive programs, however. Other processes and sound stuff doesn't bother anything.

Whichever app is open is the one that is using all the system resources. (I am running WinXP home but I can upgrade to Pro if you guys think it'll help)

Here are the things I have tried:
Virus scans
Spyware scans
Defragmenting hard drive
Increasing page file
Reinstalling drivers for mobo, sound, video
Downloading all windows updates
Tweaking certain BIOS settings

The problem persists. I am utterly baffled.

Any ideas?

 

[alizee]

First, I'd try disconnecting it from any networks, just disable them from the control panel. Is the windows installation from April as well? I would try a complete reinstall, which I know is a complete drag.