Not sure if you still have the TV but a very simple thing you can try is unplugging the wire Harness ( has about 8 wires?) that leads into the LCD screen. It's a multi-wire plug that is the last wire stage I think going into the LCD panel. It is 3/4 up from the bottom and directly centered. You'll have to take the back cover off obviously, but that is pretty simple.
I had a very screwed up display with mine when it was 1 yr old but still brand new pretty much unused. I think I remember a bunch of weird horizontal lines and strange colors making the picture look like a cartoon. It was involved in a house move, so not sure if something went wrong such as it getting set down hard or?
Anyway, I fixed mine by unplugging that wire harness, blew some canned air into the receptacle and plug, plugged it back in and the pic has been fine ever since! I was lucky I guess. It really has never given me a problem since except that it won't accept the remote commands anymore either, which went out shorty after the screen was remedied.