Fun with aspect ratios on widescreen TVs

So, my roommate has this ginormous widescreen TV, its an insignia I think. I didn't buy it or the DVD player, so I don't know any of the details, sorry. Anyways, no matter the aspect ratio of movie I'm watching, the picture always fills up the entire screen. I was watching Ace in the Hole, and it looked kind of distorted, but I had to look up the original aspect ratio and then fiddle around with the zoom button on the TV remote to adjust the movie to have the black bars on the side. Is there any way to set either the TV or DVD player so it will recognize the aspect ratio of the movie and adjust the letterboxing accordingly?

Thanks

That tree is really far away.