If you decide to remove the browser:

Mozilla maintains an official, public FTP directory of every browser release since 2004. This is the only safe, verified source.

Before clicking the download button, let’s understand what makes version significant. It was the last security and stability update in the Firefox 3.6 branch. Mozilla released it on March 13, 2012, to patch several critical vulnerabilities before ending support for the entire 3.6 series.

Firefox 3.6.28 is the lightest, but virtually non-functional for 95% of today’s web. Use it only as a file viewer or classic intranet tool .