Damn mate, that's really bad news, isn't this the same way your 280 went?
That's the exact same thing that happened to my 8800GTX and 9800GT, I managed to sort the 8800 by baking it, though it was well out of warranty, I am not suggesting for one minute that you bake this card!!!
You must be raging over this setter, I'd probably be throwing my PC out of the window if this happened to me!!!
::edit::
after reading chemicals post, I wonder if maybe your PSU could be the cause of these cards dying like this?
God knows how you could go about testing something like this.
BTW, be prepared to wait a while when you send this one back, they still haven't booked my PSU in for testing yet, it's coming on for 3 weeks since they received it now, needless to say I'm getting pretty ****** off with them now.