So, I just read this thread. I'm connecting my PC to my older Panasonic HDTV via HDMI. The desktop is displayed just fine. It is Windows Media Center that is overscanning the TV signal. I have it bringing in over-the-air signal from a tuner. I set it up to be displayed on 'Television' in the WMC set up. I can't find a way to solve this. It is definitely within WMC because the deskop aligns correctly with the TV.
Any advise would be appreciated. Thank you.