Problem with my Vizio LCD TV?

I have a Vizio flatscreen lcd tv. I've had it for alittle over a year. About two weeks ago the TV went Blue and showed a No Signal screen. I figured the comcast box messed up so I powered down both it(the comcast box) and the tv. When I powered the tv back up I still have the Blue screen. I've hooked another tv up to the box in my room and it plays fine so I don't think it's the comcast box. I had also hooked a dvd player up to the Vizio and it will play DVD's just fine. What could be wrong with it?