Microsoft issued a custom Windows Media Player plugin a couple of years ago. It seems that the download page has moved here:

http://www.interoperabilitybridges.com/windows-media-player-firefox-plugin-download

More info: Using the Windows Media Player plugin with Firefox | How to | Firefox Help

Any luck?

The question was about Win 7. The page listed in the reply provides vista but not win7.

The reply is not helpful.

The question was about Win 7. The page listed in the reply provides vista but not win7.

That plugin works in Windows 7 (tested on Firefox 4). I can't help that Microsoft hasn't updated their page.

(It also is the currently linked page here: http://windows.microsoft.com/en-us/windows/downloads/windows-media-player )