I'm very sorry to hear that has happened. Unfortunately, this sounds like it may need servicing agian. 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 recently had my power board replaced because the tv was cycling off and on. Now the tv will not shut off, I have to unplug it. Do I need another Power Board?