Open your Internet browser and go to the Mozilla Firefox download page. Click the Free Download button in the center of the page. Once the download has completed, click Run or on the download itself (usually in the lower left-hand corner of your browser window). Follow the prompts to install Mozilla Firefox.How do I find Mozilla Firefox?
Open the Mozilla Firefox Internet browser. Press the Alt key to open the menu bar at the top of the screen, and then select Help. From the drop-down menu that appears, select About Firefox. The window that appears shows you the version of Firefox you're using.