SLI not happening.

I have two 8800 GTX's and I'm currently only running one on this system. I planned to have them running in SLI, but that seems to not be happening. If i install the second card and put the bridge on and reboot I get the nVidia program on my taskbar and it says "SLI capable system" or something along those lines. If I go into 3D option and select "Enable SLI" and then apply the settings the screen will go blank. The only way I can get it to come back up is if I uninstall the second VGA and then reboot off the single one. Any ideas as to what is going on?

Thanks in advance.

I did look into the manual for support but it was very brief. It's an Asus Striker Extreme. If anyone has any experience with SLI on this board your input would be greatly appreciated. Yeah, I'm not really sure what the problem. I've installed and re installed the chipset and VGA drivers. I'm not quite sure where else to turn from here.