Hello MichaelGH, see '''the-edmeister's''' [http://forums.mozillazine.org/viewtopic.php?f=23&t=2249039 Installing and running multiple versions of Firefox.] thank you

Note that you can install Shumway as an extension in current Firefox 24+ releases. *http://www.areweflashyet.com/shumway/ You do not need a possibly unstable Nightly build. ---- Do a custom install and install each version in its own program folder to use multiple Firefox versions. * https://support.mozilla.com/kb/Custom+installation+of+Firefox+on+Windows *http://www.mozilla.org/en-US/firefox/channel/ Make sure not to start Firefox after the installation has finished.<br /> Create a new profile exclusively for each Firefox version.<br /> Create a desktop shortcut with -P "profile" appended to the target to launch each Firefox version with its own profile. See also these mozillaZine KB articles for information: * http://kb.mozillazine.org/Testing_pre-release_versions * http://kb.mozillazine.org/Profile_Manager#Creating_a_new_profile * http://kb.mozillazine.org/Bypassing_the_Profile_Manager