I am running a HDMI cord from my video card (4870 1GB), plugged into a 50" Panasonic 1080p plasma. I get a signal on the tv, as an extended desktop but with black bars all around the sides (about 1.5" all around). I am running Windows 7, and the settings for the TV are at 1080p output. What could be causing this? I have the latest Catalyst GPU drivers installed.