I noticed my XPS 630 wasn't running my 8800 GTs in SLI so I went to enable that feature in the nVidia software... but there isn't an option for it. Also, there is only one 8800 GT shown in the device manager.
I did remove them a few weeks ago when I was cleaning out dust bunnies, I checked and each is seated properly and the SLI cable is good.
Any idea what might be wrong? Which PCIe express slot do I use to check each card at a time to see if one of them might be bad? It's a nVidia 650i SLI mobo.