Yes it is possible, don't use the same profile, and you will have to use "-no-remote" on the one that is not your default browser and/or not your default profile. Start reading at: * http://kb.mozillazine.org/Using_multiple_profiles_-_Firefox A picture map of how I can start them *http://dmcritchie.mvps.org/icons/win7_quicklaunch_large.png *http://dmcritchie.mvps.org/windows-7/win7.htm *http://dmcritchie.mvps.org/windows-7/win7.htm#quicklaunch *http://dmcritchie.mvps.org/firefox/quicklaunch.htm

It's a lot easier to use a Firefox Portable version for your other installation, it won't interfere with the 1st version you have installed and you won't have to deal with "Profiles". http://portableapps.com/apps/internet/firefox_portable