How to Reset a Mac Mini Computer
Apple's Mac Mini is computer that measures 7.7 inches by 7.7 inches by 1.4 inches and weighs 3 lbs. Because of its small size, people often use a Mac Mini as an entertainment hub connected to a TV or audio system to play videos and music and display pictures. Mac Minis are also suitable for desktop computing. If your Mac Mini won't turn on or start up, or if it freezes or otherwise doesn't seem to be working properly, try resetting it to solve the problem.
Plug the Mac Mini's power cord into a power outlet if it is not already plugged in.
Press the "Power" button on the back of the Mac Mini, and then immediately press the "Command" key, the "Option" key, the "P" key and the "R" key on the keyboard simultaneously. Continue holding the keys until you hear the startup sound two times. This will reset the Mac Mini's parameter RAM (PRAM), whose settings may have been corrupted, causing problems with the computer.
Unplug the Mac Mini's power cord if it still has a problem after resetting the PRAM. Wait at least 30 seconds, and then plug the power cord back in. Press the "Power" button to start up the Mac Mini. This resets the computer.
Unplug the power cable and any other cables from the Mac Mini if it is still having a problem. Wait 10 seconds. Press the "Power" button and hold it while simultaneously plugging the power cable back in. Release the "Power" button. Press the "Power" button once more. This resets the Mac Mini's Power Management Unit, a chip that manages the computer's power. When there is a problem with the PMU, the Mac Mini may experience problems such as not turning on, failing to wake from sleep, or being unable to play videos.
Contact Apple customer support or an Apple-authorized repair center if your efforts to reset the Mac Mini do not correct the problem.