downgrade from FF 4 to FF 3.6 do you delete the following files in your profile folder(extensions.cache, extensions.rdf, extensions.ini, extensions.sqlite and localstore.rdf) before you uninstall FF4 or after you reinstall FF 3.6
in earlier answers from downgrading from FF4 to FF3.6 you suggested removing certain files from the profile folder, is this done before uninstalling FF4 or after reinstalling FF3.6
Opaite Mbohovái (2)
Though not too important, I would delete them after uninstalling Firefox 4 and before installing 3.6
Deleting the 3 extension.* files ensures that Firefox 3.6 checks the compatibility of extensions, this can be useful if an extension was updated when Firefox 4 was installed. Deleting localstore.rdf will reset the toolbars, removing the customizations made by Firefox 4.
Some extensions may have updated to versions that are only compatible with Firefox 4, so you may encounter problem with reverting to a previous version. Other files in the Firefox Profile Folder may have been upgraded as well.