You can try this extension to override compatibility issues - once it's installed, you can just re-enable Google toolbar.

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

If you still want to downgrade, see here:

• http://releases.mozilla.org/pub/mozilla.org/firefox/releases/latest-4.0/win32/en-US/
• installing firefox

I love Firefox but putting out a new version before it is compatible with the most popular ad ons is ridiculous. So is making radical changes to the look so everyone has to relearn to use the software. I am sorry but they are starting to think like Microsoft.

I have another desk computer( window XP） . I download google chrome today and try it. I love firefox and I have been using it since 2006. I will use another browser which support google toolbar.

Add-on worked & Google Toolbar running with Firefox 5. Downgrade site did not open. Why, in Firefox 5, does the new tab page not have the history & recently used pages that were in Firefox 4?

I would like to try Gryllida's solution for adding back the Norton's Toolbar. Would that work? Help, Gryllida!

Most likely. Why don't you just try and report on it??? You're the one knowing this toolbar.

but what about the info that is stored in the google toolbar

does this solution lose the info stored in my google toolbar?

This solution does not lose the info stored in my google toolbar. Great!