First of all, see if the Alexa toolbar is listed in the list of toolbars, found in menu View (Alt+v) -> Toolbars.

If it is and doesn't have a checkmark beside it, enable it by clicking it in the list in that menu. If it is and does have a checkmark beside it, it may be displayed outside the window somehow or there is some other problem, please try and see if the Navigation buttons like back, home, bookmarks and reload are missing support article can help you solve it.

If it is not listed in the Toolbars menu, it may not have installed properly for some reason - check in menu Tools -> Add-ons -> Extensions that it is installed. Our support article Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems may be able to help you, this may also apply if you're not using the default theme as it could be a problem with the theme. The article Unable to install add-ons (extensions or themes) may also be helpful and goes more in-depth with add-on installation problems.

Please let us know how above works out, and if we can be of further assistance.

Thanks for the response. The Alexa Tool bar is not listed in View Toolbars but is in the Extensions list - so I think it might be downloading ok. However, when I go to addons and click the "options" button for Alexa the entire "add-ons" page freezes. So I still don't get to use the Alexa toolbar.

Could some security software be blocking the Alexa toolbar perhaps?

Also, which version of the Alexa toolbar are you running? The one on AMO doesn't seem to be fully updated - the Alexa Toolbar page contains version 1.54, the Alexa Sparky page on AMO seems to have version 1.4.9. There also seems to be an alternative available, SEO Status PageRank/Alexa Toolbar on AMO - you could try that one too.