Z92J Strange Screen Problems

I've recently bought a Asus Z92J-Q411M Laptop. The first thing that i did was update the drivers of the ati mobility x1600 256mb with the omega drivers. But in games i was getting some shadow bugs, etc. Then i've installed the previous ones (manufacturer graphic driver), from the Asustek website. Altough sometimes (very rarely) especially when im in the internet explorer or even the windows explorer, i get some black lines all over the screen, and the screen even shrinks at the same time. But that's only for a couple of seconds (about 4-5 seconds), then it goes back to normal. It has happened about 5-6 times since i bought it (15 days ago). I've even updated the bios with the new version from the Asustek website, but the problem was not solved. Sometimes i can stop that black lines and screen problems if i move the angle of the screen forward or backwards. It is very strange, i never saw something like that. I was wondering if anybody had ever the same problem or any solution for it.

I'm very upset with it, because i've already installed many things on it and i was avoiding to give it to the manufacturer.

Thanks...