Before junking the card, try a couple things...
First, uninstall the graphics driver, reboot, and run Driver Sweeper from Safe Mode. Have it remove any Nvidia, AMD, ATI graphic
driver remnants it finds. Re-boot and install the latest driver for your card and O/S.http://www.techspot.com/downloads/4266-driver-sweeper.html
Second, run Driver Sweeper to clean your system of registry errors, junk files and other crap wasting resources. Do the Clean and the Registry both.http://www.piriform.com/ccleaner