It is my firm belief that the problem abated with rollback / restoring was purely happenstance, as the behavior with the external monitor confirms. Your LCD panel is dying. One could take a flyer with replacing it, but my experience, these specific types of cases are hit or miss. Better to just go new. . .
However, I have a laptop with no top chassis whatsoever serving as the kitchen computer. The bottom chassis is stuck under the counter. The only thing showing is a nice 19inch LCD*, compact keyboard and mouse. Good enough to check email, browse the web, and catch up on some TV episodes.
*Oh, wait, I just added a 7 port USB hub, too. . . ok, now I need to start thinking about cable management.