Try to reset the NVRAM. NVRAM are small chunks of memory that keep the files on your Mac even when the device is turned off. It doesn't hurt at all to reset the said files. It is possible that the MacBook will work again after the reset. To do this you need to follow the steps below to take:
MacBook Key Combinations:
- Hold the Command, Alt, P and R keys at the same time and then press the power button.
- Hold the buttons until the start tone can be heard again.
- Wait for the MacBook to reboot. Then you can let go of the buttons.
In some cases, the SMC (System Management Controller) needs to be reset. To do this the following must be done:
- Turn off the MacBook
- Disconnect the device from the power supply and then reconnect it.
- Reset SMC Key Combinations: Press Shift, Ctrl, Alt and Power at the same time.
- The light from the power supply cable could flicker now.
- Restart the MacBook
If you've tried all the above and your MacBook still won't turn on, you are likely dealing with a circuit failure.