Power Problem or Faulty Graphics Card?

Hi all,

I'm having a bit of a problem with my PC at the moment that has me at a bit of a loss. Recently when playing games and sometimes watching videos, I've started to experience regular crashes. While I do get a blue screen, it's a blue screen that doesn't contain any sort of error message. Everything worked fine until a few weeks ago.

I've noticed over the last few days that when this happens the graphics card appears to not be receiving any power (fan stops spinning), which explains the blue screen as this is the regular state for the monitor when it's not receiving any signal. However... the lights and fans within the PC stay on, so clearly there must be at least some power.

It's really started to frustrate the hell out of me now. It seems to happen as soon as I load a game up... even ones that don't contain really high quality graphics.

My system specifications are:
4GB RAM
EVGA 260 GTX 896MB
OCZ GameXStream 700W Power Supply
Intel CPU Core 2 Duo E7300 2.66GHz 1066MHz
Currently running Vista, although this problem started while I was running XP.

Could it be that when the graphics card kicks in when a game is loaded, that it's requiring too much power and causing the power supply to cut off? I'd just like a few opinions on this before I decide what to do. I don't want to RMA a card that isn't faulty, and I'd really like to try and avoid spending cash on a new power supply if it's not likely that's where the fault lies.

I'm sorry if I've missed something out. My brain is spinning at the moment from trying to get the damned thing working

Forgot to mention that recently when observing the system temperatures through Speed Fan, the AUX temp would rise (fire symbol would appear) just before the graphics card becomes unresponsive.

So, is the fan spinning before the bluescreen and then stops at that point? Or does it not spin at all? Having to flip the back switch on the PSU can mean an overcurrent protection was tripped, but I don't think it would still work if that were happening.

could be a bad video card...
or a bad connection.
try taking out the card, blowing out the dust from the port.
if that doesn't work... then it may be your card or your PSU.
i'd suggest trying a diff. card, but thats not usually feasible for most people

that seems to be a power issue.
either a bad cable, or a bad PSU thats not consistently giving enough power on the rail. If your PSU has another power connection that isn't used, try that one.
The only other thing is to start RMA-ing parts and see which one is the bad one