Vista - Jerky TV reception

My WMC had been displaying normal TV reception until about two days ago. Now the picture and audio is very "jerky" as though it's coming in packets that are hesitating to be decoded. My reception on other TVs connected to the same system is normal.

Actually I've found the program to be a little quirky. It always opens in full screen and for some reason the cursor will not display on the blue screen. All I can do is hunt around until I highlight a button blindly. The remote starts it, but it seems I need to activate it twice to get it to finally tune to a station. Even if I close the screen in not full screen mode, it will always reopen in full screen.