I have an old pc set up as a media centre. To record my streams, I also have an HD PVR2. When I originally installed this, I managed to get everything set up correctly without any problems. The pc sends HDMI video to the HD PVR2, which then sends it on to my Sony TV. 

I then temporarily moved the pc to another room to fix a Windows update problem. I plugged it into a 32 inch Panasonic TV. The display was distorted, but it was good enough to work on and I didn't want to mess with the settings since I intended to put things back as they were.

So I finished the work and put the pc back. And naturally now the display on the Sony is stuffed and I can't find a way to fix it. To be more precise, the display is fine if I plug the pc directly into the Sony. Everything is correct. But if I plug it into the HD PVR2, The display area does not fill the entire screen and I can't find any way to fix it. Resolution is correctly set to full 1920x1080 and aspect ratio is good. Also, there is no over- or underscan. The entire pc desktop is visible in the display, but there are black borders around the display area and it doesn't fill the screen.

The driver for the HDMI card is AMD Radeon. There are no adjustments I can find. The display device on the Windows resolution screen is the HD PVR2, not the TV. There are no other options.

So can anyone tell me what I have to do to make the HD PVR2 use the entire TV display area again? It worked before. Why won't it now?