You mentioned you let your battery charge run out, so the first thing you need to do is to charge your MacBook for a longer time till it has enough power to turn on, and then press the power button/Touch ID to turn on your MacBook.
If your MacBook is still not turning on or charging, check whether your power connections are intact. Try to insert your power adapter into another MacBook to check whether it can work normally or change to another power adapter or power supply. And then, charge your MacBook again and then turn it on again to check whether the issue has been fixed.
If your MacBook still won't turn on, try the following methods to troubleshoot.
- Detach all external device
- Press F1 or F2 on the keyboard to adjust the brightness of your display.
- Hold on to the power button or Touch ID for 10 seconds to perform a power cycle.
- Reset SMC
If the above methods can't help you to turn on your MacBook, you can send your MacBook to Apple Store to ask for help. They will diagnose the issue and replace the malfunctioning components for you.
