I need to revert to older version. Will that replace Firefox4 or will I have both?
Firefox4 is not compatible with my hp printer and my online library access does not work with Firefox4. Library says use an older version or another provider. Printer is a problem, too.
Wšykne wótegrona (1)
To downgrade to Firefox 3.6 first uninstall Firefox 4, but do not select the option to "Remove my Firefox personal data". If you select that option it will delete your bookmarks, passwords and other user data.
You can then install the latest version of Firefox 3.6 available from http://www.mozilla.com/en-US/firefox/all-older.html - it will automatically use your current bookmarks, passwords etc.
To avoid possible problems with downgrading, I recommend going to your profile folder and deleting the following files if they exist - extensions.cache, extensions.rdf, extensions.ini, extensions.sqlite and localstore.rdf. Deleting these files will force Firefox to rebuild the list of installed extensions, checking their compatibility, and reset toolbar customizations.
For details of how to find your profile folder see https://support.mozilla.com/kb/Profiles