I've got a 17in MBP from 2009 or 2010. Recently it just crashed, turned off, and then wouldn't load up again. I took the hard drive out and my other computer diagnosed the hard drive as having failed. Got a new hard drive, fresh install of OSX, it works ok until I taxed the system (about 15 min), then it crashed again. Now it won't load at all. I tried another hard drive and it still won't load. It powers on to the Apple logo screen. The screen has faint grey/blue stripes across it then proceeds to the apple logo but will go no further. I took it to a genius bar, where they said the tested the new hard drive and graphics card, and no problems. They have no more tests and said they can't help me further. I assume it's the logic board. Am I correct, and what can I do now?