- Download the XPI archive of the Flash Player Plugin to your hard disk. XPI archives are only ZIP files containing the files used by the plugins.
- Extract the files in the archive
- Copy the files flashplayer.xpt and NPSWF32.dll to %APPDATA%\Mozilla\Plugins\ where
%APPDATA% is the folder which holds your applications profiles and settings. (You can open this folder simply choosing "Start → Run → Type in %APPDATA% → OK") - Restart Firefox
- Enjoy your flash websites!