How do I force restart my imac?

How do I force restart my imac? Turn on your Mac and immediately press and hold these four keys together: Option, Command, P, and R. Release the keys after about 20 seconds. This clears user settings from memory and restores certain security features that might have been altered.

Turn on your Mac and immediately press and hold these four keys together: Option, Command, P, and R. Release the keys after about 20 seconds. This clears user settings from memory and restores certain security features that might have been altered.