Video Card Failing - How Do I Diagnose ?

Over the last few days I have been getting random and very intermittent BSOD's for the first time with Windows 7 x64.

Each BSOD during the memory dump before rebooting was making a reference that it couldn't start up my video driver or something in that nature. I have a nVidia evga 9800 GX2 with 190.37 drivers.

After a BSOD this morning, same reference as above, windows rebooted but resolution was 640x480, a quick look under device manager showed both GPU's on my 9800 GX2 had been stopped due to a problem with exclamation marks beside them but oddly I still had a display.

After the next reboot, I couldn't get into windows anymore. Not windows 7, or XP, or leopard (I am Triple Booting) I CAN however get in via safemode but my troubleshooting is not revealing much cause in safe mode, those drivers are naturally disabled.

The event viewer under administrative tools, showed a kernel-power reference during my last couple BSOD's which I believe is just me hitting the reset button when the computer was freezing up. There are no other critical references.

My initial thoughts is that something in the video card was slowly beginning to go, hence the casual BSOD's over the past couple days and now that's it. BUT the odd thing is that ALL the LED's on my video card are showing correctly, ie, if there was some kind of internal problem, there are a couple of them that should be showing red or yellow, but they are not.

Anyone have anyway of diagnosing that it is indeed my video card that is failing? Could it be the motherboard? Also, in safe mode in Windows 7, I tried reinstalling the 190.37 drivers but no changes.

Thoughts? Questions?

PS - I have tried startup (repair) and I have tried restoring to an earlier point. No changes. I am still in safe mode.