You can uninstall an addon via the Firefox Addon Manager. Click the Firefox button or Tools in the classic menu, select Add-ons, select Extensions on the left side, then find the extension in question in the list and click its Uninstall button.

I don't see the uninstall button.

The uninstall button was relabeled as "Remove" in newer versions for some reason (same thing). Each extension in the list will have its own uninstall/remove button on the right side of its listing. (Disable or remove Add-ons)

I'm still not seeing this button - can you send the url?

https://addons.mozilla.org/en-US/firefox/addon/fastestfox-browse-faster/?src=search

click on the above url and you will see there are no ways to remove or uninstall fastestfox . . .

Uninstallation has nothing to do with the page where you install it. You click the Remove button in the Addon Manager. As I said above, you open the Firefox Addon Manager by clicking "Add-ons" in the Firefox button menu or the Tools menu with the classic menu bar.

Here's a screenshot of where the button is inside the Addon Manager: http://tinyurl.com/4xsd92v

I have no idea where you are . . . I followed your instructions and don't end up where you are . . .

Thanks Dave . . . found it. Gee for a minute there I thought I was going to have to go back to IE!!!!!!! LOL