Toshiba MV20FL4 20 in. TV/VCR Combo "channels black border around screen" Questions

...black box pops up on the screen and just leaves the border area around the box available for viewing. It only happens on a few channels at a time and seems to alternate as to what channels are ...

...channels but now it is up on all of them, and it won't go away. How can I get rid of it? Hi, Just happened to see your black box problem associated with your T.V.; Thought I would pass along an idea ...