Graphic/Video Driver Problem

I’m having problem with Graphic/video driver. The only version that i can installed is 177.79(NVIDIA). I cant install any other driver that is higher than 177.79, the latest version is 185.85 if i’m not mistaken, if i do install the latest version, the pc wont start, it freezes after the GUI loading screen.
Can anyone help me with this? does anyone have any solution?
My pc specs,
asus striker 2 extreme
intel c2d 6550 2.33 ghz
kingston 1600 ddr3 2gbx2 ram
xfx geforce 9800gtx+ X2 (SLi)
tested on these OS : XP 32 Bit, XP 64 Bit(sp 3), Vista 32 bit, vista 64 bit, Seven..latest driver will not work.
Answer #1
what is the error you get? make sure to uninstall old driver, restart and install new drivers.
and what OS are you running?
Answer #2
Currently using windows vista 64 bit sp 1.
There are no older drivers, since i just formatted.
Right after vista is installed, i first installed the video driver(185.85), and then restart. after the vista gui loading screen, the screen turns black, and freezes there, the same problem occurs to the other OS’s that i have tried.