I’ve had my MacBook Pro since this summer, but just started experiencing this problem in the last couple of weeks.
I’ll have something up on the screen, such as the sign in screen to Gmail, walk away from the computer for 15 minutes, and then come back to a black screen. Normally, I would hit the space bar and everything would come up and be fine. Now, nothing happens.
In order to get something to work, I have to power it off. When it comes back up, the message “You shut down the computer because of a problem” pops up. Any ideas why this is occurring? Typically I put my computer to sleep rather than shutting down.