cod 4 freezing pc, need help

[unserious]

SOmetimes when i play 5 min and sometimes i can play hours but Game freezes my PC and only thing i can hear is stupid sound, and i cant do nothing, only restarting my PC on buton on computer.
My pc configuration:

Dual core processor
1 GB video card
Win 7 64bit

P.S. this started to happening few weeks ago, and working fine before that , i had 512 video card so i boughted 1 GB because i thought it was problem with that, 2 days ago i updated bios and drivers because i thoughted it was problem with that, but all of that camed without resaults, so please if u know what could it be . thanks

[BigPop]

try to update your grapic's card driver.

[unserious]

I tryed:
Update bios
update drivers
changing video card
update direct x
chankging resolution - in game, in windows
looking for adwares, viruses and that kind of stuff
Checking tempeture on processor and video card and RAM
looking for solution on web, and founded nothing
nothing worked
So this is my last hope to fix that problem

[Remember]

Try to Re-install game?
or Run as admin?

Close Virus Programs?

[Moto]

We need more detailed specifications of your computer

How much RAM, what specific type of GPU, CPU yep.