All we see is "no signl lock"

The screen is black with a blue "no sigal lock" in the center. If I push "TV" it goes to all blue. I can push the numbers and they'll show in the corner but nothing happens. It needs to be on 125 for our DISH. We have never seen this with any "Dish" problems so are thinking that it is the TV itself. Any suggestions will be appreciated.

I am unable to find the manual and don't know the product info so guessed with the choice LVM-37......other than it is about 38", wall mounted and has a DVD place in the center on the bottom with the controls on the right side. It is probably about 2 years old