Hello Rosiland,

Please do the following steps:

• check your plugin at first here
• Try disabling the Firefox hardware acceleration. To do so, please follow these steps:

1. Click the orange Firefox button at the top left, then select the "Options" button, or, if there is no Firefox button at the top, go to Tools > Options.
2. In the Firefox options window click the Advanced tab, then select "General".
3. In the settings list, you should find the Use hardware acceleration when available checkbox. Uncheck this checkbox.
4. Now, restart Firefox and see if the problems persist.

Thank you

Thank you for your suggestion. I tried it but it does not fix the problem. After I tired it, my computer listed Silverlight as up-to-date. But when I tried to watch a training video, I got the following message: "This plug-in is disabled. Manage plug-ins . . . " (I clicked on this message and my computer still listed Silverlight as up-to-date.)

With the last Firefox upgrade, some plugins are no longer enabled until you enable it.

Open the Add-ons Manager by Pressing the Alt or F10 key to bring up the tool bar. Followed by; Tools > Add-ons.

Hot key; <Control> (Mac: <Command>) <Shift> A)

On the left side of the page, select Plugins.

Go to the web page. Once the page is loading, mouse to the address bar and LEFT click the icon. A window for displaying site information should come up. Select More Information. Look thru all the menu items and check all of the settings.

Plugin Status: This page says that the Silverlight Plug-In is up to date. But this does not solve the problem: When I try to watch a training video, the screen is black & tells me that plug-ins are disabled. The video works with Safari but not with Firefox. However, I want to use Firefox. Thank you for your help.

Maybe this article will help?

Use the Silverlight plugin to play audio and video