1. Go to THIS PAGE
and download the BIOS for your motherboard. Run it while in windows environment and follow instructions. If flashed successfully go to next step.
2. Download the latest nVidia driver from THIS PAGE
. (Assuning that your 8800GTX is installed correctly and plugged in to 6pin PCIe power connector) Uninstall your current "on-board video" driver and reboot your system. (while doing this keep your monitor connected to on-board VGA port.) Once uninstalled your graphics will be very laggy because the system will use native windows driver, dont panic). Reboot your system again and go into BIOS, in "on-board devices" menu disable your on-board VGA and enable PCI-e as your ptimary VGA. (this might not be the options, just make sure your onboard VGA is disabled) Exit and save your settings. When your machine reboots your monitor will no longer work through your motherboard. Connect your VGA (or DVI) cable to 8800GTX and start the system.
3. Install the nVidia driver you downloaded in step 2 and reboot the machine. Adjust your display settings and enjoy!
p.s. some of the terms I used might not be the same in you BIOS menu, just use the common sense and do not overclock your 8800GTX without proper. cooling used. I do not take any responsibility for this tutorial or your hardware in case of failure, use it at your own risk!. Good luck!Edited by Russkiy - 6/3/09 at 6:20pm