It has sadly thought you were taking the piss playing at 1440p and rebelled. Sorry to say the GPU looks goosed. Warranty? :/
Read my signature thread for help! Really this all needs to be processed via the original purchaser of the GTX 680.
GIGABYTE go by serial number rather than where it was bought as far as I know. You should be safe. If not, get it done through your colleague if you can and then get the card back from said colleague.