So your thinking maybe the heatsink might be putting pressur on it the wrong way. I guess that's possible. I will have to give it a try. I would like to get this working if possible so my son can use it. He is still using integrated graphics.

That sounds a bit terminal to me :s

 Any other time I've seen anything like that, the card's been toast or overheating and we know it's not overheating.

 Given you have a waterblock, check it's been reseated right, and also make sure the water is flowing!