The rig in my sig is hard locking after an hour or so of COD4. No sound, still picture displayed on the screen, requires hard reboot. I'm running a fresh install of XP Home 100% up to date and all my drivers are the latest. There is nothing installed but COD4 and Firefox. Immediately after the install I ran Memtest for 5 passes with no errors. Then ran Prime95 blend for 24 hours, no errors. Then Prime95 large fft for 24 hours, no errors. My BIOS settings are all at default. Any ideas what could be the problem?