Issue with new GTX 260 (probably PSU)

I recently purchased an EVGA GTX 260 from newegg and have had absolute failure trying to use it.

GTX 260 card
ABS Tagan BZ 800W PSU
Asus Rampage Formula Mobo w/ Intel Q6600

I've been using this system for about 6 months with an XFX 8800 GT and I've had almost no problems at all.
However, after I installed the 260 today, I could barely get windows to boot before my screen would lock up. Often it would lock up even before loading windows.

It seems pretty obvious to me that it's a problem with my power supply, especially because my voltage LEDs would occasionally be red when I would try to start the pc.

I don't know much about PSUs, but this seems really odd because I'm fairly sure that my power supply shouldnt have a problem powering a 260, right?

After buying this card, I'm pretty broke, and I just thought I should look here for opinions or advice before I just return the card and settle for a 9800 or something for a while.

No, I didn't...