it doesnt matter what i am doing.  It just randomly freezes all of the time.  I cant move the mouse or anything and i need to hit the reset button and restart.  It did the same thing when i was using xp (using vista now)  Sometimes it freezes while playing cod4 too.  It started when i installed my new psu and gpu. What do you think? Hi!!! ...   please list your system spec's..... Did you defrag?.... Do you have all your up to date drivers?.... Have you OC'd CPU or GPU?.... I don't think a new PS will cause this unless the unit is real low on AMPS.... Could be Vista....However.... are you sure all parts of the old OS or divers are gone?  GOOD Luck !!!!!my specs are over there but i forgot to update it.  Updates are a 1kw antec psu and a 4870.  All my drivers a good. Defrag wouldnt fix itHi!! I didn't see if you OC'ed the CPU or 4870.... You could try a reinstall of cod4 .... also did you run a Reg cleaner or a program cleaner? Check program files and see if an old program or one you are not sure of is showing.... You could run a Mem test (I have 4gb).... VISTA IS A MEMORY SUCKER (lots of things running in the background).... good luck again..... "It started when i installed my new psu and gpu."

Do you have the old PSU and gpu to swap out and test which one is the culprit?

Alan <><  What does SpeedFan say?i have my old psu and gpu though I cant test my new gpu on my old psu.  That just wont work but I will try to see.  My gpu tems are low, about 36 C idle and while running folding at HOME (gpu 95% load) is about 52C and is says that isnt too hot.