Got a weird glitch in COD4

I have CoD4 for PC and i opened it up after installing, but as soon as the Infinity Ward logo pops up the audio starts to pop in and out for a split second every other second. When I am in the main menu and in game the popping audio is synced perfectly with a spike in graphical lag, it goes from 40fps to 1fps over and over again.

My computer has E8400 3.2ghz , 4 gigz of ram, and a 8800GTS 320mb. (psu 700wtz)
OS: Windows XP professional 32-bit SP3
I am going to upgrade my card soon as christmas gets here.

Anyway I was just going to ask if this is a driver issue with XP sp3? or is the driver corrupt? or maybe its just that game. I play other games on here like WoW , Farcry 2, and Fallout 3 and it played those games. Fallout 3 does crash randomly sometimes but on other occasions it will be stable for hours.

I downloaded the drivers for my card off the nVidia website and installed it back in the middle of October.

SOOooo any ideas

Well installed the drivers that nVidia released recently and the game now runs at max settings with normal frame rates