Yes, the bridge has been installed. SLI is enabled via nVidia Control Panel which loads with nVidia drivers (using newest made available on 11/6/07).
No matter how I do it, once 2nd card is installed, it is found, but properties in Device Manager prompt CODE 12 - not enough resources, remove whatever to free up resources. Even with a fresh install of the OS, WIN XP SP2, or VISTA ULTIMATE, same prompt (fresh install precludes IRQ hogging).
I appreciate the help. I think the BIOS on the propietary SLI board of DELL is what is the cause of the problem. The BIOS/chipset have been updated with no relief seen.
Lastly, the two cards do work in SLI on another PC. They were removed to allow an upgrade to 8800ULTRA. I yanked the two 7800gtx cards that came with the DELL, which were found, and worked in SLI. I sold them. The new PC had EVGA 8800gts OC which I removed to install in th DELL. The DELL is now my everyday machine for anything but my gaming. It's a shame that I have this extra card which I am reluctant to sell on eBay. Maybe someone is out there who found a way to overcome this problem on their DELL XPS 600.
Enjoy the coffee. Make mine cafe royale!!!