Well, I'm an asshole. And an emoticon-abusing one at that. Sorry about that guys (insert coy winking smilie here).
I got that card today. I was so excited. It looks so shiny. But it didn't fix the problem. Turns out I had missed a big sign - I didn't notice that the keyboard lights didn't stay lit after a few seconds after turning the machine on, which is typically a motherboard-related issue.
Oh well, now I have two working video cards, and a really nice new card. Thanks for the help again.
I think I'm going to grab this, and this time assume that the mobo is the problem:
Newegg.com - GIGABYTE GA-EP45-UD3R LGA 775 Intel P45 ATX Intel Motherboard - Intel Motherboards