Hi my name is ***** ***** I will be the expert working with you today to help and resolve the problem you have posted.
Delete the files extensions.* extensions.rdf, extensions.cache, extensions.ini, extensions.sqlite and compatibility.ini in the Firefox Profiles/profile folder to reset the extensions registry. There will be new files created.
Disabled file extensions that are not compatible on the next start in (Tools > Add-ons > Extensions) click "Find Updates" button to do a compatibility check.You may have to (Reset all user preferences to Firefox defaults) on the "Safe mode" start window.