Code 43 Error - 7900GS - Vista Business - Need help!

Ok, I've been using vista on my pc for about 2 months and its been working perfectly.

Until last night when I launched World of Warcraft and about 10 minutes into playing my PC just crashed, the screen was frozen, couldnt do anything but reboot it manually.

Launched the PC up again, was working fine until about another 10 minutes in, it crashed again, rebooted.

I booted up again, started Team Fortress 2 and it did the same thing.

So once again I rebooted, and didn't wana play any games so I decided to watch some Family guy in VLC media player, about 5 minutes in my pc crashed again.

Then, went to reboot it and it wasn't outputting video to the moniter, so i unplugged the video card and plugged it back in again and tried to boot it again, didnt work. So i found an old PCI gfx lying around and put in my pc, it worked. I got the popup saying one of my vga adapters has been disabled etc, and i got 'Code 43'. I've tried system restores and reinstalling drivers but it is still coming up with errors.

Before it started the errors I installed a Cisco Aironet 350 wireless pci card (and drivers etc) into the system, im not sure if that did anything but i dont think it has effected the PC because I have taken it out and tryed booting etc.

Can anyone please help me?

thanks

PC:
Intel Core 2 Duo e6400 2.13ghz
2gb Ram
Inno3d 7900 gs
Gigabyte GA-965P-DS3
Seagate 320gb HDD