I own a 17inch MacBook Pro late 2011. While working on Photoshop I experienced a screen distortion with vertical strips and then it got stuck. I was forced to restart but I couldn't pass by this screen.
I tried everything. Resetting PRAM, checking disk in Single User Mode (sbin/fsck -fy), I was able to mount a drive and back up my data. Sometimes, I was able to boot normally, but I had the same issue again after a while. Finally, after many attempts, I was able to boot in recovery disk and reformat my os, I did a clean install. At first it seemed to work fine and I upgraded, all happily, to El Capitan. While still testing the Mac if was working properly, I had the same issues again. Now, no matter what I try, it refuses to do anything except Single User Mode.
What's wrong? Is it the logic board? Is there something I can do? Unfortunately, Genius Bar is not an option as I moved away from uk.