That's sadly called abuse but any tech will tell you it means that some connection may be less than perfect. You've told enough for a good tech to dive in so I'll stop here.
I have a Samsung LCD "LN-" model, 40" TV that is about 5-years-old. Over the past few weeks it has developed a flicker that ONLY appears on the left side of the screen. Often this is accompanied by a dark bar that divides the screen in half and (only) sometimes it has a image trail on that side of the screen. I hate to say, but I can usually clear this up with a sharp smack to the side or top of the set. Anyone? Thanks.