cannot restore old firefox profile

I realise this post is not exclusively related to Windows 10, but someone out there may be able to help me.

I carelessly ended up with a virus today and it played havoc with my Firefox browser. Fortunately a couple of weeks ago I had saved a copy of my Firefox profile with all the bookmarks, extensions and passwords etc. . The problem is that when I place this profile file in its correct location, Firefox will not open. I receive a message saying that 'Your Firefox profile cannot be loaded. It may be missing or inaccessible.

This situation is probably due to the fact that shortly after saving my Firefox profile, I created a new user account for Windows 10, and then changed its name via the Control Panel. The original name for the new account however still appears in File Explorer under C:\Users as I could not change it there.

How can I get my original Firefox profile to open? I cannot understand why it is not working as it was fine until I got the virus earlier today.

All suggestions gratefully received!!

Florio

Did you use the proper tool to backup MozBackup - Backup tool for Firefox and Thunderbird
Have you checked the permissions they may be owned by the other name?
Did you FF sync on if so they will all apear when you login
Restore bookmarks from backup or move them to another computer | Firefox Help

Once you put your profile in the correct location ("C:\Users\UserName\AppData\Roaming\Mozilla\Firefox\Profiles" and renamed the original profile which you can later delete if you wish) copy the full name of the profile you wish to use open the profiles.ini file which is in the same folder with notepad and change the name of the original profile in Path=Profiles to the one you want save and it should work. You might need to take ownership of profiles.ini

Further information about the .ini file: Profiles.ini file - MozillaZine Knowledge Base