I have a Dell Latitude D600 and at random times the display will flicker with horizontal lines. I can sometimes agitate it by gently twisting the LCD and it will flicker. I've done some research before and thought the problem would be the flex video cable, which I ordered and installed, but it still flickers. The LCD looks cosmetically perfect, as well as the inverter. The display backlight isn't flickering, rather there are white lines that flicker randomly, so I don't think it's the inverter.
I hooked it up via VGA to an external machine and only the laptop suffered the flicking so I believe that the graphics card is fine.
Here's a video on what I'm talking about. Dell Latitude D600 Display Flickering - YouTube