I don't know what you've done when you say that you have "transfered my entire old computer" but that isn't going to transfer a PostgreSQL install. If you have poker data you want to transfer then you should do a backup on the original computer and then that can be restored when PokerTracker 4 and PostgreSQL are installed on the new one:
Guide: Backup & RestoreYou can do a clean install of PostgreSQL by following
this tutorial and then manually download and install PostgreSQL v12 available
from here. Using a Mac administrator account or administrative privileges install that PostgreSQL and for the password boxes use "dbpass" (no quotes) which is what PokerTracker 4 uses by default. If that doesn't get things going then please open a
Support Ticket where a technician can give you further assistance.