Installing the ActiveX Plugin
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"Salva destinazione come"

Firefox 1.0, 1.0.1, or 1.0.2

a. Firefox 1.0.3

b. Firefox 1.0.4, or 1.0.5

c. Firefox 1.0.6

d. Firefox 1.0.7

*The Firefox 1.5 plugin is a test version - it is not known to be
problem-free yet. https://pfs.mozilla.org/plugins/?application=firefox
 
  Info (English language): http://plugindoc.mozdev.org/

 Full Step-By-Step Guide: Embedded Windows Media in Firefox