I have been playing with Deepin and getting crashes.  For one, I tried the video capture program "Cheese."  Suddenly, the display crashed.  I tried to recover with various key combinations, but nothing could restore the display or get me out of the crashed condition.  Another time, I tried to change the screen resolution and the display crashed.  Again, the system would not respond to any combination of keys on the keyboard.  Are there ways to recover from a crash without just shutting down the computer?   I hate to "brute force" a shutdown because of the possibility of corrupting system files.  

If anyone can recommend a good resource for learning Linux fundamentals as they pertain to Deepin, I'd appreciate the reference.

Thanks!