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/
After having my Samsung LCD LN40A550P3F for 3.5 years I have several vertical lines running through the screen (blue, yellow & red) the TV. This happens on the screen when you are watching cable, dvds, or playing any gaming concole. I think that its ridiculous for a tv only a few years old to be expeircing issues more disturbing is that im not the only one who is having these problems. I am very disappointed that Samsung is unable to back their products. After complaining to Samsung their response to me was... check the connections and make sure they are secure... do you not think i checked those on my expensive tv?? do you think i wanted to face a repair bill to buy another tv?? After telling them that the connections were secure their final answer?? Your warranty is expired any repairs are your responsibility... THANK YOU SAMSUNG you have lost another customer and let me tell you, you have lost a vocal one that likes to praise companies when they so deserve and rip them when its needed. I will never buy another Samsung Product...My decision to go Galaxay III or Iphone has just be resolved... Iphone it is.