New TV (Panasonic HD), new Shaw digital box. When I first turn my TV on my remote works. I can view guide, change channels, scroll up and down. After an hour (??) or so, no rhyme or reason in time line, the only thing I can get my remote to do is mute and volume change, cannot change channels, look at guide, scroll up and down. Do I need a new digital box? Do I need a new remote? Any thoughts?