You should try or find out if the games work in Firefox 6.0.2 first.

For those that really need an earlier version of Firefox, find your system and the Firefox version you want in releases, download and start the install.

• ftp://ftp.mozilla.org/pub/firefox/releases/

or with the latest of version 3

• http://www.mozilla.com/firefox/all-older.html

Note Mac OS X 10.4 user, and Mac OS X 10.5 users without Intel cannot upgrade to Firefox 4 or 5 0r 6+.

When reinstalling Firefox from a download, Firefox must be down once the installation starts. When the installation finishes, don't let the install start firefox for you. Instead end the install and start Firefox in your normal manner, thus preventing creating a new profile which does not have your bookmarks cookies, etc (but your old profile would still be around and would).

If you are going to go back to 3.6.22 turn off your Firefox updates first Tools > Options > Advanced > Update or you will end up in Version 6 automatically later, and without warning.

Another good source for previous Firefox versions:

ftp://ftp.mozilla.org/pub/firefox/releases/

edit: replaced random unofficial download site link.