That's like some strange effect straight out of hollywood, that greeking nonsense. Although I had it once too. Not sure what I did, wish I was, because I am on the virge of doing it again, this puppys hot.
Ah bummer.. I would try new drivers using the external hookup, of course you've tried that though. A replacement of the basic screen is how much on ebay or here? That's probably your solution, which sucks.