Display on screen has lines. Macbook Pro

Hey everyone, im new to this forum, and pretty new to macs, so i would really appriciate your help here. I got a macbook pro from a family friend and she wants it fixed (i do a bunch of computer repair, just mainly on pc's). I really dont know where to go from here, i checked the cables on both ends and hooked up an external display... Youtube link shows a video of what it is doing.

Macbook Pro Problem - YouTube

It appears to be a bad LVDS cable, which by the way is a common problem with some of the older MacBook Pro models as they get brittle from the heat and either become intermittent or fail. You can disregard GPU troubles since the external display is showing fine. Here's a LINK where the cable can be purchased. ($31.00)

You might want to shop around and look for something less expensive in case it turns out not to be the cable. Usually they can be found on eBay. You might want to take a look on iFixit: The free repair manual.