Hi, welcome to justanswer.com! My name is Mike.I am going over your question and I will be with you shortly.
1. Shut down the computer.
2. Disconnect the power adapter from the computer, if it's connected.
3. Remove the battery.
4. Press and hold the power button for 5 seconds.
5. Release the power button.
6. Reconnect the battery and power adapter.
7. Locate the following keys on the keyboard: Command, Option, P, and R. You will need them in step 9.
8. Turn on the computer.
9. Press and hold the Command-Option-P-R keys before the gray screen appears. You have to do it pretty fast if you miss it just shut down by holding the power button for 10 seconds then start it up and continue with step 6).
10. Hold the keys down until the computer restarts again at least twice.
11. Release the keys.
Did you try that?