I was using Firefox when my MacBook Pro crashed. I was not initially concerned, as it does this about once a month. However, it no longer starts. It had 80% battery when it crashed, and plugging it in does not help. Before I take it to the shop or take it apart, I hope someone here can offer a solution.
It is a 2013 MacBook Pro running the latest version of Yosemite.
Edit: The computer restarts after several hours, but crashes again later. I sought professional advice and was informed that the logic board needed to be replaced, because the not-restarting bit is apparently symptomatic of an overheated logic board. But the problem resumed two days after a new logic board was installed.