Symantec need to update their Firefox add-ons so that they are compatible with Firefox 4. They have indicated that for Norton 360 they plan to release an update to Norton 360 to support Firefox 4 in early May - http://us.norton.com/support/kb/web_view.jsp?wv_type=public_web&docurl=20100720113635EN&ln=en_US

I do not know about the time scale for updates for other Norton products. Pending the update by Symantec, if you want to use the Norton add-ons you will need to downgrade to Firefox 3.6.

You will need to contact Comcast about their plans to make their toolbar compatible with Firefox 4.

If you want 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

Will you be notifying Comcast when Norton is compatible with Firefox v4 since Comcast supplies Norton to all Comcast users? This would be very helpful if did a mass mailing to all their customers....Thank You.