If you have run Thunderbird, it will have created a new empty profile. Hopefully the computer shop saved your old profile for you.

I would close Thunderbird, set the computer to show hidden files, navigate to the new profile and copy the old one over it. That means the profiles.ini file and the accompanying folders, Profiles and another inside that, usually with a name made up of a string of random numbers and letters, ending with .default

Hi Zenos - this is not my area of expertise. I can find the files (I have several addresses in TB, and each has a group of files in the profile area). How, exactly, do I copy these files? I highlight them, but 'copy' is not an option. I'm sorry, your solution needs to be a little bit more A-B-C for me to be able to use it. I am readily able to shoot myself in the foot, but this is kind of out of my league. Thanks for an answer in one-syllable words, if you can.

You use your computer's file manager - Windows Explorer in Windows.

You can open two separate Explorer Windows, one looking at the old profile, the other at the new, then select, drag and drop from one to the other.

Or, working in a single Explorer, navigate to the old, select, right-click, then navigate to the new, right-click and select paste.

You can always use ctrl+c to copy, ctrl+v to paste. I think there is an Edit option on the menu to help with copying and moving. And if in doubt, right-click.

I will give it a whirl, thanks. Though I feel reasonably competent, I did graduate from college before even the calculator was available. Slide rules, yeah!