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

Only work with Copies, work while closed and do not transfer the issue back into the new profile.

• https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data
• https://support.mozilla.org/en-US/kb/recover-lost-or-missing-bookmarks
• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox
• https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles
• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

What's What in the Profile :

• bookmarks and history: places.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)

beardsleytom said

I tried to "refresh" firefox and it hung up. After 20 minutes I gave up and restarted the computer. Now, I can't open Firefox and I can't install firefox. ...

Twenty minutes is a long time for the Refresh process to run, based upon my experience with it, but restarting your computer deleted all the Profile data that was running in RAM during that process; plus it may have done more "damage" that just your Profile data being lost.

Have you tried to uninstall Firefox thru the Windows Control Panel, before trying to reinstall Firefox?

Also, it might be best to try to install Firefox using the "full, off-line" installer from here. https://www.mozilla.org/en-US/firefox/all/

Thanks to all who have responded. My solution happened in the meantime. While I don't recommend shutting down during the refresh, that's what I did after the 20 minute frustration period. After the problem in the new installation, I went into "Find Everything" (an app on my desktop) and searched for Firefox. I had already deleted through Control Panel, Programs and Features. "Find Everything" brought up the appdata folders, both local and roaming. I deleted both, crossed my fingers and did another reinstall which worked. All the passwords came back, add-ons, favorites... Only the graphic icons on the favorites were blanked out - not a big deal at all. Again, thanks for your help. -Tom