I seem to have the same problem on my MacBook Pro Late 2012 15 Inch. I am unsure of what the problem could be. Because the laptop will turn on displaying horizontal green lines across the screen. Then show the loggin with a white background and the green lines. And once I add my information to log in it'll show a loading bar stop half way through. And restart turning it's self off and back on again. If anyone knows how to fix this please contact me back