I dropped my 15" MBP retina about 6-8 months ago slightly denting corner of screen. The screen then had around 10 horizontal lines running through it, and a bad dark spot in the corner. However it was still usable, and 80+% of the time it's hooked up to an external monitor w/ lid closed so i elected not to repair A few days ago, i start getting a lot of sudden reboots. Then i couldn't get it to power up at all. It would turn on, but to a black screen, the caps lock key would illuminate if pressed [edit:no display on external monitor either]. Eventually i got it powered up and attached a fresh drive for Time Machine, in case it put out a corrupt backup on my existing TM drive. Next morning it had finished the 500GB backup no problem. Bought a new MBP and successfully loaded the TM backup onto it. On the broken MBP, i'm trying to get it to boot w/ Cmd-R so i can do a format/fresh OSX install to see if that fixes any issues and prepare to sell it as-is or with a new screen. But i'm wondering if the logic board has now gone bad and it's going to cost too much to repair..