It is not unusual for a port to die. If the card is under RMA you could return it to the OEM for another if you decide it is bad. It is also possible Windows registry has an issue. So first thing do you see anything on the DVI port when booting like the Bios but then Windows doesn't show. That would be an example of Windows being messed up. You could also boot then to like a linux flash drive and see if the port works from there. Or move the card to another computer for testing.
