Vertical Lines on Hitachi LCD TV

For a couple of days my HITACHI LCD TV has problems displaying images on one side of the screen. The left shows some colorful vertical lines while the other half is fine. Somebody advised to just unplug the TV for five minutes. I did that but the problem remained. This is not going on all the time. Often enough the TV works fine; other times it comes on and I cannot do anything to make the lines go away. Does anyone know more about this problem?