philips flat panel tv screen problems

I have a Philips 42' flat panel tv, model #42PFL3704D/F7. One morning I turned it on & there is a large block or verticle strip down the screen that shows no picture. Changing the channel, the input, volume, adjusting the screen settings, turning it on & off & everything else I can think of to do to it besides chucking it throught the window has made any difference at all. It covers more then a third of the screen! I moved it into the bedroom & put a smaller one in it's place hoping some sort of solution would come my way & two monthes later I am so fed up with sitting on the floor so I can see the smaller tv I plugged it in hoping for a miracle... yeah... So here I am... If anybody has any ideas I would be glad to hear them... I can send photos or whatever might help identifying the issue. Thank you soooo much for your time.