macbook pro won't turn on

Take a look at the steps suggested by Apple in this article:

If your Mac won't turn on - Apple Support

Try Safe Boot:

- Shut down your Mac

- Wait until your computer turns off and after that press the Power button

- Right after you hear the startup tone, press and hold the Shift key

- Release the Shift key when you see a grey Apple sign and the progress bar below this sign

- After your Mac boots up, restart it as you usually do.

Apart from that, take a look at this Apple article and follow the instructions on Resetting NVRAM shown there: How to Reset NVRAM on your Mac - Apple Support

Try resetting the System Management Controller: https://support.apple.com/en-us/HT201295

Hope this helps!

It appears that you have to enter a Firmware password. If you do not know it, you will have to take the MBP to a Apple store:

https://support.apple.com/en-us/HT204455

Ciao.