Fiddling and searching on the SSD or old hard disk is quite hopeless.
Again: the WiFi password is setup in the router.
What does the sticker on your router show?
Only a password? (<password>)
User name and password? (admin, <password>)
What happens if you enter this in the browser address line and open:
192.168.1.1
What's the manufacturer and model number of the router?
What is your internet provider (ToT/NT, 3BB, AIS, ....)?