Along the same lines - just bought a HP-2700 Laptop with a Intel-Duo Core T5550 64-bit processor, running Windows Vista-Home Premium. I installed COD4 on the machine with no problem. Application runs fine until I actually go into a game (either single or multiplayer). Once inside a game, the display and response slows to a crawl. I realize this notebook is not the optimum solution, but I should be able to run the game at lower graphic settings with reasonable response. At the current levels, it is unplayable and very frustrating.
I'm an old hand at COD4, but new to 64-bit OS and Vista. In fact, not even sure if my Vista is 32-bit or 64-bit version. It was OEM install. If anyone can provide some useful info or links to resolve this, I'd be very grateful. I'm fixing to go on the road and would really want to take COD4 with me. Thanks in advance "pistol_pete"