my pc underforming?

i know it should just be in hardware but that gets ways less reads so i put it in both.

my rig:

Q6600 @ 2.4 ghz

3 gig RAM (2 x 1024, 2 x 512)

8800gtx with 169.28 drivers

vista basic

playing all games at 1440 x 900 -

crysis barely playable on very high (around 20fps) - playable on high but with no AA (25-30 fps + on average)

- on later levels is lagging heavily even on high

company of heroes - high settings and 2xAA but starts lagging when 4 + players on skirmish or in intense battles

forged alliance - highest settings without AA and still lags even on early missions sometimes

Solution: Remove Vista, Vista slowers pc's much

ps. In fact XP is better OS for games