I am doubtful ti is a driver conflict. I still got the drivers for my 3870 installed even though they haven't been loaded in months it still doesn't cause me issues but I am someone who makes sure that my system works before hand. As for you chances are that you may have a bricked card but rule that out by testing your card in another machine.
There may still be a chance of there still being a warranty. Contact customer support and tell them about the problems that you are having with your card and see if they will help you out or go ahead for rma.