Cod4, Cod5 Gaming Problem

i could play games fine in x32 but i seem to be having troubles in x64, i have tried a number of things (compatibly mode including when installing, reinstalling without game updates, with updates)

i installed 2008 x64 redistribution pack and made no difference.

tried the windows update 179xx wddm1.1 display drivers (ppfft)

tried earlier disp drivers

uninstalling physx

crysis (with or without game updates) locks in the menu, thats in the rare occasion it does make it into the menu otherwise it sits at a black screen until you press space bar to close the inaccessible "this programme has stopped responding" dialog box

cod4 mw locks at mission loading screen and needs forced reboot

cod5waw when i select to start a mission, select difficulty and it just goes back to the mission select page no matter how many times you try it??

i use my system mainly for gaming so this is really doing my head in.

i have nforce 20.08 forceware drivers

182.06 geforce drivers

along with the latest physx software

all 64bit drivers.

running on 790i ultra, 9800gx2 quad sli, q9550, 4gb ddr3

rest of specs are in my profile.