I bought a new PC with Windows 10. The technician at the store downloaded Thunderbird at my request, but when I got home I realized I had not asked him to migrate my old Address Book into the new PC. I still have the old PC, so I assume that I can copy and paste my address book from the old PC to the new one via a flash drive. Problem is I don't know how to locate the address book file in order to copy it. Can someone show me how to do this? Or if there's a better way, I'm open to that as well. Thanks in advance.