I have sudden lockups in Call of duty both expansion and regular, this never has happened before until i got my new mobo , cpu, i have a athlon 64 3500 939 with msi neo2 plat mobo, nforce 3 ultra, This is the only game that Completely locks up my computer. I can play all of my other games for hours with 100% stability. Only Call of duty. im not sure if the game doesnt go good with 64 bit cpu's or what, sometimes the game runs great for like 30min, then eventually it will just totally lock up, and make a very fast clicking noise coming out of the speakers, it will continue doing this until i press reboot on my case, everythings locked when it freezes. i have a 9800 pro , with corsair xms 512mb x2 (1gig dual channel). like i said this never did this until i got my new cpu , amd mobo.. i had a a7n8x deluxe mobo, with 2500. My cpu temp seems fine around 120F. i've tried MULTIPLE gpu drivers, and its just weird that this is the only game that it does this on. when it freezes up , it keeps making that fast clicking noise out of the speakers until i reboot, or shutdown manually through case. sorry for long post. if any of u have any ideas i would apreciate it.