How to Troubleshoot a MacBook Boot Problem

Disconnect any external devices and peripherals from the computer. Press the power button. If there is no response, proceed to Step 2.
Locate the small battery meter on the left side of the MacBook where the ports are located. Press the small button to the left of the LEDs. If they do not light up, the issue may be a dead battery. Connect the computer's power supply and press the power button. Proceed to Step 3 if the computer does not boot up.
Disconnect the power cable and wait a minute before reconnecting it. Press the power button. A small LED on the tip of the power cable should light up when connected. If not, remove the plug and check the power port for debris or dust. Gently blow air into the port and into the plug connector and reconnect it.
Hold down the 'Command' key, the 'Ctrl' key and the power button at the same time for three seconds. A chime or tone should emit from the computer before it starts up. If not, proceed to Step 5.
Press the power button and immediately hold down the 'Command/Option' key, the 'P' key and the 'R' key at the same time until you hear at least two instances of the chime or tone.
Disconnect the power cable and turn the laptop over if it still does not turn on. Remove the battery. On early 2009 and older MacBooks, locate the coin-slot locking mechanism and turn it with a coin until the battery pops up. On mid-2009 onward MacBooks, remove all of the backing screws and lift off the back. Locate the battery and use the pull tab to lift the battery out of the compartment.
Hold down the power button for five seconds after the battery is removed. You should hear a long tone that lasts a few seconds. Replace the battery and power supply and press the power button once more.
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