After about 4 years the cable from the motherboard to the display fails. ikenfixit.com or notefix.com may be able to fix it.
My dell latitude cpi is having display issues. When you boot the machine docked or undocked you get a garbled screen with intermittent lines running up and down and you have to move the mouse up and down just to see the full image. It basically has this big white band running across the screen about a quarter of the way up. I know it isn't the monitor because as I have said some of the time you can get it to boot up and you have the full screen. The bastiges at Dell told me the machine is too old to give me any answers. Well, my car is nineteen years old and I can still find parts and a mechanic to work on it, so that answer isn't cutting it.
Please let me know what might help. By the way Neomagic is involved and I don't know how to get rid of that either.