Yes I have several versions of firefox installed. Firefox 3.6 is still supported and secure, then there are the Beta, Aurora & Nightly channels. I am guessing the other channels by default install in there own locations rather than overwriting your current installation, if not choose a custom install option. This is considered an advanced topic, generally used by developers etc CARE do not uninstall and take an option to remove personal settings, however that is worded, as that attempts to remove all profile data from all installed versions of firefox, you will loose passwords and bookmarks etc. Use separate unique [[profiles]] for each version, or you will get problems. * See http://kb.mozillazine.org/Using_multiple_profiles_-_Firefox * http://kb.mozillazine.org/Testing_pre-release_versions#Installing_multiple_versions