Problem with new ati 4890

Hey guys,

I've recently bought an ati 4890, it had been playing fine for about 3 days.. when suddenly today the pc wont boot up.

The card seems to go through it's normal post/start up process over and over ie:

the 3 red lights flash, fan goes on full.. then slows down.

Then happens about 3-4 times before the pc beeps in anger. And no display what so ever.

Any ideas if this is a broken psu or card, or anything else?

Help GREATLY appreciated.

Cheers.