Firefox can find plugins in several locations, but Firefox 21 changed the location of the "shared" plugin folder so older installers like the Microsoft Windows Media Plugin no longer drop the DLL file in the correct location.

There apparently are two ways to address this:

(1) Change a Firefox preference so that Firefox checks the old location. Here's how:

(i) In a new tab, type or paste about:config in the address bar and press Enter. Click the button promising to be careful.

(ii) In the filter box, type or paste plugins and pause while the list is filtered

(iii) Double-click plugins.load_appdir_plugins to switch its value from false to true.

This will take effect after you restart Firefox.

(2) Copy the plugins folder to the new location. Here's how on Win 7 64-bit:

Open a Windows Explorer window to:

C:\Program Files (x86)\Mozilla Firefox

Right-click and copy the Plugins folder

Double-click the browser folder to open it

Right-click and paste

Right-click the new copy of Plugins and rename it to plugins

After restarting Firefox, the plugins in that folder should now be available.

Edit: I suggest just doing #1.

Hello jscher2000. Thank you so much for your reply. i tried this. I followed your directions, note that what you called filter was labeled search on my computer. I was able to change value to true on "load-appdir etc. and restarted computer and firefox. I checked to see that the value was still on true after restart. I did not see the windows media plug in on my list of plug ins. I was not able to hear my conference because the window still said I needed a plug in for my browser. It may be that I am not doing the download correctly. I am sent to interoperability bridges download site. I click on download, it asks me to allow change on hard drive. I accept I get a welcome to windows media player download site. I click on next and get a screen that asks me if I want to change repair or remove. What do I do then. I have tried repair and that doesn't seem to work. If I try change, I don't know what to change to. The net result is that now I have a value that says true, but the plug in is still not on my list of plug ins that I find after I click on tools/add ons/ plug ins. Any thing I am doing wrong? By the way, how do I get back to this question from the support home page?

If you get the Change/Repair screen, it means the installer detected that you already installed the plugin.

Do you see the file here:

C:\Program Files (x86)\Mozilla Firefox\Plugins

Its file name is: np-mswmp.dll

If the file is missing, I suggest removing and then reinstalling the plugin.

Edit: By removing and reinstalling I mean using the Remove button below the Change and Repair buttons in the installer, then running the installer again to reinstall.

To find your questions, you can either (1) open your profile page (drop-down menu from your username along the very top edge of the page) or (2) open the "Sort and Filter" section above the questions and use the "My Contributions" link (https://support.mozilla.org/en-US/questions?filter=my-contributions).

Hello Jscher2000 As you suggested i removed the old windows media player installation by using the remove button and the reinstalling. When I reinstalled I got a different screen asking me to accept the terms and then to complete the installation. It took a few minutes, but the windows media plug in did appear and when I checked the plug ins it was up to date and when I went to the website I was able to hear the conference call. Thank you very much for your help. Jessbee

@jscher2000 THANK YOU!! You're a legend!!!! Followed your steps and now I can see the plugin. Now I can listen to my favorite radio station online! THANKS AGAIN!!!