CPU Usage - 100%

Hello all, my CPU usage claims to be at 100% whenever I exit a game, it feels like my computer thinks the game is still running, thus causing my computer to run slower in desktop. This is very annoying, whenever I exit a game I just restart my computer to fix the problem. Any help is appreciated, and I've noticed I'm not the only one with this type of problem.

get procexplorer and see what process is peggin ur cpu then at least we know where to start. Process Explorer

I'm not sure if this will help, but:

This is my computer while waiting sitting in the main menu of Fallout 3: CPU100Problem.png picture by Schofield14 - Photobucket

This is my computer after exiting Fallout 3: CPU100Problem.png picture by Schofield14 - Photobucket

The CPU Usage STAYED at 100%!