I have a 52"big screen TV,rca.. it has a black square that is covering up most of the picture,you only can see the outer edges of the picture that you are watching but when you touch any button it shows the full picture for about half a second then the black square appears again... was wondering how can you take it off, I went into the menu and couldn't find anything to take it off...

Do you have Picture In Picture?

It could be closed caption also.