I have the PC configuration below: AMD Phenom II 920 AM2+ 4GB DDR2 6400 Corsair XMS memory EVGA 730a Motherboard OCZ GameXStream 600W Power Supply Point of View 8800GTS 640MB WD 640GB SATA II HDD WD 250GB IDE HDD Whenever I try to play high definition video files and games such as TF2, Batman: AA, etc. the computer freezes or the video/game is very choppy. Any suggestions? Also when the desktop refreshes it goes black for about a second sometimes. Also high def images and streaming video like YouTube also freezes.