I have a Toshiba 50H82 and something strange has happened. I normally watch everything with the screen size set to full. I assume this is the best mode as the others show too much stretch, or cut off at the top/bottom. Now, I can't select "full" which is option 4 I think on the screen size menu. It is greyed out and the cusrsor skips over it. I can select any mode but that one. What have I done? And how can I get this back? I'm using a HD DirecTivo if that makes any difference.