Try <removed random unofficial download site> Keep in mind that version is no longer supported. Quote from Wikipedia "End-of-life 31.x.x ESR product line on August 11, 2015".

For Firefox release history see... https://en.wikipedia.org/wiki/Firefox_release_history

Mozilla does not make older versions as something you can just download on mozilla.org as easily as current versions due to potential vulnerabilities.

Only 41.0.1 and 38.3.0 esr are supported.

Since you have Windows and want to use a old 31 ESR version for one thing there is the portable Firefox option. This will not touch your Firefox install and Profile settings. Firefox 31.8.0 esr was last however portable apps only did up to 31.7.0 for the 31 esr.

http://sourceforge.net/projects/portableapps/files/Mozilla Firefox%2C Portable Ed./Mozilla Firefox ESR%2C Portable Edition 31.7.0/

(copy and paste whole part for link into Location (address) bar

The English options are near bottom of list.

Thank you! I was able to retrieve the version that I was looking for and thanks for the warning regarding the older version..

Thanks again!

Pappy1972, that site does not even have the Fx 31. ESR builds and there is no need to download from there when all Firefox Releases are available from mozilla.org like say http://ftp.mozilla.org if you must download a older version.