MacBook Pro Serial Number Not Available
The best way is you should ask Apple to fix this.

If you wanna DIY (WARNING: at your own risk), with a tool named Blank Board Serializer (ver 1.1 part number 063-7137, please google it if you want), you can set your serial number onto your Apple computer board. There are some step by step video that should be found easily on YouTube.

Steps:


Burn the BBS disk image to a CD/USB.
Boot the compute and press the option key (i.e. the Boot Picker).
Insert the CD/USB and select it for booting.
Once the Blank Board Serializer has started, follow on-screen instructions.