Post originale di: Dan ,
Before you alter the systems drive how about creating a clean bootable USB thumb drive with the same or newer OS. Follow this guide: [http://www.macworld.com/article/3092900/macs/how-to-create-a-bootable-macos-sierra-installer-drive.html|How to create a bootable macOS Sierra installer drive]. Once you boot up exit the installer and then see if WiFi works going into the preferences setting. Is that working? If not you have a problem within the logic board power services powering the Airport board. If the external drive works then you have a messed up OS install.