Try one of these articles:
- Update Firefox to the latest version Firefox automatically updates itself by default but you can always do a manual update. Learn how to update Firefox on Windows, Mac or Linux.
- How to download and install Firefox on Windows This article describes how to download and install Firefox on Windows.
- Install Firefox on Linux This article will show you how to install Firefox on Linux.
- Install an older version of Firefox Downgrading usually doesn't solve Firefox problems. This article gives you links to old versions of Firefox and some alternatives to downgrading.