What causes my screen to go like this?

Hi there :)

I recived my sisters macbook a few weeks ago. She did not want it any more because its screen do not turn on like it should.

I tried to google the problem and at some site it was stated that it might be the LSVD cable that needed a change. So i bought 2 different cables, replaced the original one, but with no success.

in these 2 links i show how the MacBook boots and what the screen looks like after it turns back on from black screen :)

1.video: Here is the normal boot. it boots into a white screen.

http://www.youtube.com/watch?v=hEydnV0HM...

2.video: From sleep. Different colors.

http://www.youtube.com/watch?v=lSrpcd8fm...

As for external monitor, it works as intended. But its not as practical if i have to bring an external screen with me to university every day ^^

Hope some one here would be able to help me fixing it for less than than the price of a screen assambly - and tell if that would even work :/

// Maxymilian