Most likely you have a faulty LCD panel tabs. This can be verified sometimes by turning set on and tapping or squeezing the top left side of the TV. The only true fix is to replace the panel. I've been told that Samsung may offer to replace the panel or give you a discount on a new TV. Samsung is know to have LCD panels with premature tab failure. So it may be worth while to contact Samsung and see what they can do for you. There are videos on youtube that show case the problems and show you how to patch the problem. just type in "LCD panel tab" in the youtube search box.