You have the LCD, the cables and the motherboard.
If you want to try, replace the wiring (cables) since that would be the cheapest possibly bad part. In fact you may have a clue that's it. For example the laptop is opened and closed many times a day.
I have laptop hp compaq nc6120. When I switch it on, on monitor appears big fat horizontal line (almost half a screen).
Here is a photo http://goo.gl/dCWfN
If I plug it on external monitor, picture is fine.
Can I fix it somehow, without buying new LCD screen?