Q: Screen frozen, press power off message

Hi hpfromsp,
 

Thank you for contributing to the Apple Support Communities.
 

It sounds like you saw a message on your Mac telling you to restart the computer. This is most likely an Apple message relating to an error known as a "kernel panic."
 

You can find troubleshooting steps to help with this situation in OS X: When your computer spontaneously restarts or displays "Your computer restarted because of a problem."
 

Best Regards.