Persistent nv 14 (vid card power shortage) and crashes, help!

I just got a new custom built system, specs as follows:

Intel Core i7 920 (quad core @ 2.67 GHz)
Asus P6T Deluxe (Intel X58 Chipset)
3GB DDR3 1333MHz RAM
750W Corsair TX PSU
Western Digital RE3 WD1002FBYS 1TB 7200 RPM
Antec Nine Hundred Two Case

Into this I placed the EVGA NVidia 9800GT from my old system (which I replaced because of repeated hard drive failures, either because of a bad disc controller on the motherboard or possibly a bad power supply).

I am getting periodic BSOD's, each one accompanied by a massive list of NV 14 errors in the event log (that's insufficient power to the video card, as I understand it).

To my knowledge the power supply I have should be more than sufficient, is that correct? My BIOS is up to date, I've tried placing the card on different 6-pin cables, I'm not sure what else to try to solve this problem. Needless to say, I'm sick of mid-game crashes due to this issue. Any help in diagnosing and solving the problem would be greatly appreciated. Am I right to suspect that the card may have been damaged by my previous computer? Should I just replace it? Anything I should try first?

Thanks very much for any help.