I can’t find the serial number

affordable33 wrote:

I’ve been trying all the key options ti be able to turn on my Mac Pro, but none of it is working. So it still has a question mark in the front when turning it on.

What is the issue..?

If your Mac starts up to a question mark

https://support.apple.com/en-us/HT204323

You posted in the MacBook Pro Community but are asking about a Mac Pro. Which is it? If it is a MacBook Pro, turn over the computer and read the serial number printed on the bottom of the computer.