MacBook Pro will not boot, begins to load then hangs with white screen I am unable to get my MacBook Pro to boot. It turns on, and the Apple logo + loading bar appear however after a minute or so of loading it eventually changes to a white/grey screen and just hangs. 

The machine is a 15-inch MacBook Pro from early 2011 running OSX 10.10.5. 

I have booted in verbose mode and I couldn't spot anything untoward however similar behavior was observed, just in verbose mode.

I can get to a shell with cmd+s but I'm not too familiar with OS X so I'm not sure where to begin looking for hints about the failed boot.

I tried to enter recovery mode by booting and holding alt and was able to get the screen up where you pick the recovery drive, but I experienced the same failed boot behavior as described above.

Prior to all this the laptop had a bit of an episode where the video went very funny, top half of the screen at the bottom, and the bottom at the top with some horizontal bars of random colors, like colorful TV static... And it flashes a bit like this just before it hangs at boot... leading me to think it might be something video card related but this is my only clue so far...

Can anyone help me as to where to go from here? Such as boot logs found from the command line, or diag commands I can run?
This is a known issue - More about that here:  https://www.apple.com/support/macbookpro-videoissues/

Luckily there's a free MacBook Pro Repair Extension Program. You can lookup your MacBook serial number if it's covered by warranty.