If you have access to the old hard drive, you should be able to recover it right from the profile folder that's left on there. See Recover important data from an old profile for more information.

Hope this helps.

If both the old drive and the new drive are plugged in then all you need to do is to transfer the related files from the profile folder on the old drive to the profile folder on the new drive.
The profile folder is in a hidden location in "AppData\Roaming".

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

You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page.

• Help -> Troubleshooting Information -> Profile Folder/Directory:
  Windows: Open Folder; Linux: Open Directory; Mac: Show in Finder
• https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data

You can copy files like these with Firefox closed to the current profile folder to recover specific data.

• bookmarks and history: places.sqlite
• favicons: favicons.sqlite
• bookmark backups: compressed .jsonlz4 JSON backups in the bookmarkbackups folder
• cookies.sqlite for the Cookies
• formhistory.sqlite for saved autocomplete Form Data
• logins.json (passwords) and key4.db (58+) or key3.db (57 and older) (decryption key) for Passwords saved in the Password Manager
  if you only have key3.db then make sure to remove an existing key4.db
• cert9.db (58+) or cert8.db (57 and older) for (intermediate) certificates stored in the Certificate Manager
  if you only have cert8.db then make sure to remove an existing cert9.db
• persdict.dat for words you added to the spelling checker dictionary
• permissions.sqlite for Permissions and possibly content-prefs.sqlite for other website specific data (Site Preferences)
• sessionstore.jsonlz4 for open tabs and pinned tabs (see also the sessionstore-backups folder)

Thanks for the replies. So I found the Profiles folder as stated above and I basically dragged the entire Profiles folder into the new drives Profiles folder but nothing happened. One thing I forgot to mention earlier is that the old hard drive was using Windows 7 and I am currently using Windows 10. Don't know if that matters. What else can I do now?

Dragging the profile folders won't work because Firefox hasn't located those profile folders.

What you can do is copy the contents of your old profile folder into the new profile folder that your current Firefox is using. If you don't know what folder is the new one, it's the one listed on the about:profiles page in Firefox.

Wesley,

  I am trying to do what you're telling me to, but my lack of computer skills is preventing me to finishing the job lol. So I have both old and new Profile folders open. I don't understand what you mean by copying the contents from the old folder to the new one. I opened the Logins file and it opened a web browser page with all of the login/password data, however, I can't seem to get that data into the new Login file.

It is best not to copy/transfer full profile content, but only transfer specific files that you need like I posted above and replace existing files to avoid issues (some files may not be compatible).
If you would copy a full profile folder then you may have to edit profiles.ini as well to register a profile.

Sorry for the delayed response, Dave. Like cor-el said above, sometimes it's best just to copy certain files from the profile folder. In my experience, I don't think I've ever had a case where copying the entire profile over caused an issues, but I guess it's better to be safe than sorry.

In your old profile folder, there are a few files that you should copy. Specifically for logins and passwords, you will find the key4.db file and logins.json file. If you copy those into the new profile folder, you will be asked to overwrite the empty files in the new profile that Firefox is currently using.

If you are interested in recovering your bookmarks and history items, there's also a places.sqlite file that can be copied.

Hope this clears things up.