Do you mean the Firefox browser? Firefox will install with a program folder and a settings folder, and will add some keys to the Windows registry. It mostly keeps to its own folders and should be easy to uninstall if you decide you don't like it. When you first install Firefox, you have the option to make it your default browser. In that case, links from other Windows programs (other than browsers) and saved HTML documents will open in Firefox instead of Internet Explorer. If you aren't sure you want that, you can decline to make Firefox your default browser and just open it when you want to use it. By the way, you can get Firefox on this page: https://www.mozilla.org/firefox/ That is a quick download which connects back to Mozilla's servers for additional files. If your security software doesn't allow that, you can download the full installer instead, from this page: https://www.mozilla.org/firefox/all/ (scroll down to your preferred language) Hope this helps.

'''[https://support.mozilla.org/en-US/kb/uninstall-firefox-from-your-computer Uninstall Firefox from your computer]''' {web link}