Rebooting the computer would not have changed anything. Are you sure you did not 'reset' the computer?

Look on your desktop. Do you see a folder called; Old Firefox?

https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles

https://support.mozilla.org/en-US/kb/how-run-firefox-when-profile-missing-inaccessible

Yes. You are correct. I should have said completely reset my computer to factory settings and wiped it clean. Should I continue the procedure you sent before or is the data just gone?

That depends on just what you did.

Did you re-format the disk? Did you only reinstall the computer system? Did you delete/remove anything?

Were non-system programs/data removed? Is your computer account still there?

Is Firefox still on your system or did you reinstall it? Have you tried running Firefox? Any problems?

I reset my computer form the "Recovery" menu in settings. I did do a full reset at the end of the process which took many hours. I backed up some of the data the I thought I needed but might have missed this one.

Firefox is working good for me. I might as a last resort sync my other computer with this one to receive some of my bookmarks.

Okay. Any problems let us know.

You can look for a C:\Windows.old folder.

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile