Snowy Picture, Toshiba 42HP84 plasma tv

We experienced a snowy picture across entire the screen until the t.v. appeared to "warm up". It was fine until you turned off the tv and then started it back up. It wasn't every time you turned it on. Then, it became more frequent, and now, we have nothing but the snowy picture. You can see images moving, and sound and everything else is fine. It doesn't have anything to do with the signal. More like something burnt out.