My tv had sound but no picture, but now there is no sound either but with an image if I put a flashlight to it?

Flat screen Polaroid TV picture was flickering for some days and today it went black but still had sound. I turned it off and turned it back on it had picture for a few seconds but no sound so now it has a black screen and no sound but if I put a flashlight to it I can see an image but no sound. Please help