Horizontal Lines on Laptop Screen

[crisscross]

I have a Dell E6410 and of late I have noticed that my system hangs with horizontal lines on my screen. No keys work and I have to hit the power button to shut down and restart.

It's a Core i5 with Intel Graphics running Windows 7 64bit.

It's under Dell cover and they already replaced the screen and motherboard but the problem continues.

I have a screenshot here. Any ideas on what could be causing this?
http://imgur.com/IUGIU9q

Thanks!

 

[paul878]

Do you get that screen when you first turn on the computer?
Hook laptop to external monitor, does it show the same problem?

looks like cable or actual gpu problem.