Games dont run on Vista x64??

Hello there, I have been having huge problems with Vista 64-bit. Hardly any of my games that i had on my previous computer work on this one. I need to know how to fix these [problems

my specs: core 2 quad q6600 @ 2.8 ghz
2x8800GT in SLI
4GB Kingston 1066mhz ram
antec 900 case
asus p5n e sli mobo
lg 20x dvd writer
asus 22" w222 monitor
logitech g15 gaming keyboard
logitech g5 battlefield 2142 mouse

games that dont work: crysis, doesnt open at all, used to open but no ingame menu. happens with 32 and 64 bit applications

gears of war, can play the prison escape but says runtime error and closes after the scene.

unreral tournament 3: opens to ingame menu but if i click on anything it stops responding all together.

crysis demo: worked fine b4 i installed the full game but now it doesn't work even after uninstalling the main game.

call of duty 4, runs fine no prob. warcraft 3 runs fine too

halo ce, has sound but no in game picture showing

I would like to know how to fix these problem

You could always right click the program go to properties, click the compatibility tab, and find where it says compatibility mode, and choose a different windows version at which to run the program.

It should let you run the games with no problem

Stop using Intel & nVidia.

Seems like time to Upgrade to XP
(Most PC gamers are dual booting)