fieseler

i didnt have chance to do a clean gfx install (thanks for that, im gonna do that if it goes wrong again!) but i did reinstall normally & reinstall cod4 & disabled desktop composition & ran in compatibility mode for xp sp2.

I think it has something to do with windows experience scores/aero. If you play the game normally, ie no compatibility emulation etc. You will notice that windows tells you that aero has been disabled. Even when cod is minimized, the aero glass theme is still disabled. So i think that when the game boots up, it starts running with aero enabled, then disables it - so cod4 thinks that your pc doesnt use aero theme (which hogs resources & some of direct3d or something) but when the game boots, it detects that is aero enabled, which is using resources & other pieces of software (possible directx?) so it thinks the pc is different. disabling desktop composition disables aero before the game boots so it fixes it.

well thats my theory anyway