I was able to make my screen look just like that by using the picture size button on my TV remote to set the TV to "Wide Fit". When I was done looking at that, I used the same button several times more to return it to "Screen Fit". This is Samsung terminology – other brands may vary a bit. The basic idea is that most widescreen TVs have a mode for stretching out old-style 4:3 content for people who don't like black bars on the sides.
