How do I get rid of a black box that appeared in the lower right hand corner of my TV. I can't find the remote that came with the TV because we use the remote that we got from our cable company. The TV was unplugged for about 5 hours because of carpet installation and when I turned o the TV this black box was there. I have talked with my cable provider but they say they've never heard of this and it was suggested it might have something to do with a preview button on the remote.