Reinstalled Win7, then Norton Security, then Firefox. Then I restored a Firefox profile from 2014. The end result is that the toolbar is/was disabled by Fx with no apparent way to enable it. This could be a remnant from the Fx profile restore?
If there's supposed to be another addon in Plugins, there is none.
Open Norton and same says: Safe web=on, Antiphishing=on, Identity safe=on, yet none display either in Fx, toolbar choices or a webpage. Norton Toolbar=configure. Configure takes you to a webpage essentially saying to enable the addon setting that is currently disabled. However, as you can see by the attachment, there is no enable/disable box.
Mark