The Accelero cooler may have killed it.
Accelero 5970 coolers have been known to damage the DVI ports and this is from properly installing the cooler using the instructions.
I was looking for something for my 5970 because the fan rattles and is really loud.
Which is another common problem with reference 5970s.
This Accelero cooler is the only air cooler I could find but, after hearing all the problems with it I decided not to buy it.
It's a shame because the only other option is water cooling and this would cost about as much as another card.
Then again a water loop is something I have wanted to do for a while.