Re: I have 14.0.1 but websites are telling me I need the newest FF in order to work!
You can check the installed version via Help (Alt + H) > About Firefox. Your Firefox version is being detected on websites as 3.5.4 (please see the section on the top right). You can try to filter for the word useragent in about:config, right-click on every instance and Reset.
In the Location bar, type about:config and press Enter. The about:config "This might void your warranty!" warning page may appear.
Click I'll be careful, I promise!, to continue to the about:config page.