Low FPS, good card, MW2

Hello all,

I have had a problem with my PC for the last couple of weeks which is really puzzling. I have had MW2 installed now for months and it's been playing really well. High frame rates (around 150) with 1680x1050 res and standard game settings. Then, a couple of weeks ago, the FPS dropped to about 15-20. I checked the temps of my CPU (50 deg. celc), and my graphics card (45-55 deg.), did a Memtest for 6 hours which was fine. Then I stress tested the processor, fine. I reinstalled drivers several times, and nothing.

So I reformatted. Installed the current driver, and it played fine for about 30 mins, and then the FPS dropped back. Switching the computer off for a day and then resuming yielded no improvement. More playing with drivers, nothing. Removed graphics card, cleaned, checked all connections, nothing. Then I installed ATI 10.2 driver, and it was fixed for about a day, then last night, back again to about 12-20 fps. I've tried drivers again, no luck.

Can anyone help? I'm guessing it's either the PSU that's gone bad, or the graphics card. I don't have any other games to test, but video plays fine.