The PSU should have plenty wattage for the system if it isn't damaged. Which OS are you using? Can you disable integrated graphics in the BIOS an see if it runs well? Windows should automatically install the drivers if you are using Windows 7 or 8 I believe.
OS is Windows 8.1. I assume it can install the drivers if it ever gets a chance to boot with the Nvidia GPU.
Did you update the BIOS? I had a system that was super flakey even getting the thing to display anything on POST, and it was working fine until I tried a newer card. Update the BIOS solved it.
Good suggestion. I'll try it.
Start troubleshooting by turning off UEFI features and disabling the IGP.
I'm assuming you've re-seated the graphics card in the primary slot and checked the power connections. Also check if there's an updated motherboard BIOS in case it's a simple (but rare) compatibility issue.
There's a chance that the card was damaged during the move. Do you still have the old system to test it in?
If I turn off IGP, will I be able to turn it back on if nothing works? We have reseated the GPU in the initial slot, as well as the power connectors for it. I can try turning off UEFI. Nah, he doesn't have anything functional enough to try the GPU in anymore. We could use my system, although that doesn't sound like a lot of fun yanking it from where it is installed and mucking around in it. But, if necessary, we could try his GPU in my rig, and my PSU in his rig.
All of this is giving me a headache! But thanks to everyone. All ideas are welcome!