I tried your guide on my Gigabyte EX58 board with a Gainward 8800GTX, and it worked perfectly!

I used it for days... Then for some reason I did a reinstall.. No different to the install I had previously done... and now when i try to install the 8800GTX, when i reboot, I get a black screen, with only the top right part of the bar at the top showing, and when i click on things, they appear..

Before when i first tried it, I even did the 10.5.8 update, and everything was working fine.. Now when i do the update, and select the About My Mac thing, the screen just fades out and disappears, and goes like a light blue colour, and sits there..

I havent changed anything in my BIOS etc when i reinstalled.. I have done so many installs now, and i cant get this to work again.

Have you or anyone any idea what might have happened? Cos it was working fine..

Please help..