Symantec have a history of being slow when it comes to updating their software to work with new releases of Firefox. They have already indicated that they will not be updating Norton 360 to make it work with Firefox 4 until early May.

If you want to go back to Firefox 3.6 pending Symantec updating their software, you can 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 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

thanks tony e, i had a feeling that might be the case, so i went ahead yesterday and uninstalled 4 and reinstalled 3.6 (did not select "remove ff personal data" as you also mentioned). back with 3.6 now and will wait for symantec to "get with the program" (pun intended). thanks for replying.