I was originally using this post to test possible configurations for Windows Media Player to work with Firefox on Windows Vista. So far nothing works. changing the mime type is useless. Altering the object and embed statements does nothing. Firefox simply won’t find the right plugin to display Windows Media files on Vista at the moment. While I’d love to blame Microsoft for this one, I think the Mozilla crew needs to come up with a fix because the way the player works in a Web page hasn’t changed that much and should still work if Firefox knew how to function properly with Vista. In the meantime, if you need to embed Windows Media files in a Web page and have them work, you’ll have to either use IE or use one of the hacks to make Firefox use the IE rendering engine.
UPDATE: Microsoft now offers a Windows Media Player Plugin for Vista and Firefox.