Note Windows 7 and other windows have hidden files, make sure that you will be including them in your backup. Make sure you will be able to see all of your files when copying. :(this is from step #10 in http://dmcritchie.mvps.org/windows-7/win7.htm ) :My Computer, Tools(or View), Folder Options, View :Hidden files and folders : (_) Don't show hidden files, folders, or drives : (X) Show hidden file, folders, or drives :[_] Hide empty drives in the Computer folder :[_] Hide extensions for known file types :[_] Hide protected operating system files (Recommended) '''before starting as a precaution backup your entire profiles folder''' # observe Window-7 '''hidden files note '''(below) # type '''about:support''' into the location bar # click on "Open Containing Folder" # make a note of the filename, it contains your profile name # go up one directory to your '''profile''' folder, the profile folder contains your profile and any other profiles you might have. # go up one more directory to your '''firefox''' folder # back up your profiles folder, and your profiles.ini file to a (preferably) empty USB thumb-drive. I prefer using XCOPY myself, but you can copy from one Windows Explorer window to a Windows Explorer window that shows your thumb-drive. Hold the '''Ctrl''' key '''while dragging''' the folder and the file to the thumb drive you must see '''Copy''' not move when you drag them over '''Your main reference from this point on is''' * '''http://kb.mozillazine.org/Using_multiple_profiles_-_Firefox''' Download 5.0 from the download link on '''http://www.mozilla.org''' (don;t use the .com link it will try to update your 3.6.18) : Ctrl+J will bring up the downloads manager (in Fx5 it closes at end of download, so get used to reopening it) Start the install, as custom, install the application into its own directory, not the one that your 3.6.18 is in. You will probably haveit through Firefox 7 so you may want to choose something different than how I named mine :C:\Program Files (x86)\Mozilla Firefox 5.0\ At then end of the download, do not let it start firefox, your old Firefox is the default. Rename the new firefox 5 desktop shortcuts so you can identify them as Fx5 You need to change the properties so that the target is something like "C:\Program Files (x86)\Mozilla Firefox 5.0\firefox.exe" -p Firefox-Five -no-remote The name would be what you chose when you installed, that name will probably last you through Firefox 7. so choose the directory name well when you install Firefox accordingly. That "-no-remote" is what will allow you to run both at the same time later. Since this will not be your default browser other applications such as email will not recognize this browser unless email is web based and you started from this browser. You can play with Firefox 5 as long as you start it with -no-remote You can later copy your old Firefox 3 profile into your Firefox 5 profile and test some more. You can make Firefox 5.0 look like Firefox 3.6.18, see numbered items 1-10 in the following topic [http://dmcritchie.mvps.org/firefox/firefox-problems.htm#fx4interface Fix Firefox 4.0 toolbar user interface, problems (Make Firefox 4.0 look like 3.6)] I would suggest coloring of toolbars to identify your 5.0 from other profiles, at the very least create a folder named "**Fx5**" at the leftside of the bookmarks toolbar.

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 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 these mozillaZine KB articles for information: * http://kb.mozillazine.org/Creating_a_new_Firefox_profile_on_Windows * http://kb.mozillazine.org/Shortcut_to_a_specific_profile * http://kb.mozillazine.org/Using_multiple_profiles_-_Firefox * http://kb.mozillazine.org/Opening_a_new_instance_of_Firefox_with_another_profile