MacBook Air won’t turn on.

Hello,

Try the following steps in order until your computer powers on:

Make sure the power adapter is connected to the computer and plugged into a working outlet.
Make sure you are using the 45W Mag-Safe power adapter that came with your MacBook Air. If the power adapter stops charging the computer and the power adapter indicator light does not come on when you connect the power cable, try unplugging it and plugging it back in to position it correctly

If the problem persists, restore the computer to default settings by pressing the Shift, Left Option (Alt) and Left Control keys while holding the power button for five seconds.

Press the power button
then release it and immediately hold down the Command, Option, P, and R keys until you hear the startup sound a second time. This action resets the PRAM memory (RAM parameters)

To use Apple Hardware Test on your MacBook Air:
1
Disconnect all external peripherals from your computer, except the power adapter.
2
Restart your MacBook Air while holding the D key.
3
When the Apple Hardware Test main screen appears, select the language for
your geographic area.
4
Press the Return key or click the Right Arrow button.
5
When the main Apple Hardware Test screen appears (about 45 seconds later),
follow the on-screen instructions.
6
If a problem is detected, Apple Hardware Test displays an error code.
Note the error code before proceeding with support steps. If Apple
Hardware Test does not detect a hardware fault, the problem is likely software-related

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Best regards.
Pierre