FireFox Add-On Compatibility Reporter -- Enable GOOG ToolBar - and other Resources

https://addons.mozilla.org/firefox/addon/add-on-compatibility-reporter/


User Switcher Agent -- Emulate Internet Explorer & Other Browser from FireFox:

https://addons.mozilla.org/en-US/firefox/addon/user-agent-switcher/?src=api

Plug-In Checker:

http://www.mozilla.com/plugincheck/

Probs With Add-Ons:

http://support.mozilla.org/en-US/kb/Add-ons%20are%20disabled%20after%20updating%20Firefox

http://www.oldapps.com/firefox.php

http://www.oldversion.com/Mozilla-Firefox.html

http://www.mozilla.org/en-US/firefox/all-older.html

http://www.ask.com/web?q=where+can+i+download+older+versions+of+firefox%3F&search=&qsrc=0&o=0&l=dir

http://www.mozilla.org/security/known-vulnerabilities/firefox36.html