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/
I bought a Samsung 40" LED TV 2 years ago, last night there was a cracking sound came from the TV and it just went off. I have checked the cables, plug, etc but all are ok . I can't believe the life of my TV has ended in just 2 years , I had my old set for 12 years , I am very disappointed !