PSU damaging graphics cards?

Hi,

About three weeks ago my BFG 8800 GTX gave up the ghost. In the middle of a game it crashed and rebooted. There were lines all over the display, including the bios flash screen. The card itself was also extremely hot to the touch.

I used the BFG rma service and received a 9800 GTX as replacement two weeks later. Everything was fine for about three days until while playing a game I got a 0x0000016 BSoD saying that it was dumping memory, timing out on the display driver and shutting down. When I touched the card this time it was just warm. Now it continually gives me the BSoD while booting (just after the words microsoft corporation with loading bar appear).

The only way I can enter windows now is through safe mode or if I have the graphics card disabled in device manager. When I do I can see little orange or blue dots on any white background. My mouse pointer makes them disappear but others appear at random. I've tried uninstalling/reinstalling drivers, newest and older versions, system restore and re-seating the card to no avail.

I'm assuming it's the gcard gone wrong and contacted BFG again and hope to get the replacement replaced.

So, my question is, was it sheer bad luck and coincidence or do you think it's possible something in my pc has broken these cards? For example a faulty power supply? Wouldn't it damage the other pc components too? The system is completely stable apart from the graphics card issues.

Thanks.

Windows Vista 32
Intel Duo E6850 3.00GHz
ASUS P5K
2GB RAM
Corsair HX620W Modular PSU