LCD Problem half the screen is grey!

Hello,

My Macbook Pro 17" A1212 MA611LL/A is having a odd problem, after searching for a couple weeks with no answers I figure this is the place to get them.

Problem:

The bottom 1/3 of the screen is permanently grey(horizontal lines).

The Middle 1/3 of the screen is grey some of the time, and when it is grey it has vertical lines running through it.

The top 1/3 of the screen is fine.

So far:

I've ruled out memory, by using only one stick at a time...also rotating in a functional stick from my PC laptop. Doesn't affect problem.

I've ruled out a faulty gpu, the DVI output is perfectly fine. The picture comes in clear on an external display.

I've almost ruled out a bad cable. I've opened the macbook, the connection to the MB and Display are good. The cable looks kind of shabby cuz it's old, but the display doesn't change at different angles when I move it.

It's not the OS cuz i booted Ubuntu from disc and it's the same thing. Now I'm reinstalling OSX and I will make sure everything is up to date and run some hardware diagnostics.

I'm not sure what the display inverted does, maybe that's the culprit.

Any advice? bottom line, what part should i replace?

when middle third is working:

http://s9.postimg.org/o4hsgce73/2013_07_...

when middle third is not working:

http://s23.postimg.org/6wif5b6ij/2013_07...