1. Glad I could the bit that i could
2. I would consider doing a reinstalling windows just to rule out software stupidity Have a look
here
3. My guess is that as wierd as it sounds, it is a B&W2 peculiarity ... because everything else seems to fall within expected performance parameters (ok on the lower side of things ... can you play BF2 @ 1024x768, everything to max in the game, drivers set to performance/balanced mode flawlessly each time, everytime? ... dont go by a fps number, go by gameplay experience)