I'm very sorry for any inconvenience this may have caused you. Unfortunately, this sounds like it may need servicing. Here's the thread where you can get details on setting that up: http://forums.cnet.com/7723-13973_102-542437/service-issues-click-here-for-help/
My 2 yrs old 55 inch TV model UN55B800 XFXZA keeps turning off and on by itself! It is very frustrating! There is no light blinking on the screen!