In order to uninstall a possibly unwanted extension, please do the following:

1. Click the menu button and choose Add-ons.
2. Once the Add-on Manager has opened in a new tab, click the Extensions button on the left side of the window.
3. You should now see a list of your installed extensions on the right side together with buttons on the right side of each extension.
4. To remove an extension from Firefox, simply click the Remove button. You should see a message that informs you about the successful removal of the add-on.
5. Note that some add-ons require a Firefox restart to be removed completely. To perform a Firefox restart after the add-on removal, click the Restart now link in the message.

You can find further information about uninstalling extensions in the following articles:

• Disable or remove Add-ons

• Remove a toolbar that has taken over your Firefox search or home page

Net Nanny is a stand alone program. It is a filtering software. Not an extension or add-on.

How is the problem manifested? For example, do you get an express message from NetNanny that the site is blocked, or a certificate error, or a time-out/server not found?

An earlier thread about NetNanny not supporting Firefox 33:

"Connection was reset" error for https sites after Oct 14 update

Not sure whether they have an update for Firefox 33 by now.