I've had a problem with my PC for a while now, it will shut down/crash whenever i try to play games like Football Manager or watch HD films in full screen mode. This started happening when i upgraded my graphics card. Thought it might be my PSU as it was only 300W. Upgraded to a 500W PSU at the weekend and am still having the same problem. Any ideas anyone? A mate said it might be the processors overheating?