Bing home page video area was blank for me, although I did get the pause control. Thinking it might be a script issue, I enabled facebook.net on the NoScript menu and reloaded the page. The video and a row of small images quickly appeared. I disabled scripts from facebook.net and the video stayed, so I'm not sure whether that was relevant, or I just needed to reload the page. Either way, not sure why the delay.

But... you're saying that even the direct address to the video does not work for you?

Before tinkering with other Firefox settings, have you considered updating your VLC? I think in the past it might occasionally have caused issues with Firefox's native HTML5 video player, and your version is about 18 months old now.

http://www.videolan.org/

I can go to the link and the video plays fine. However, what I'm referring to is the www.bing.com homepage. Sometimes the page is animated. My issue is, with firefox, it doesn't play the animation. If I use Chrome or IE and go to bing.com the animation automatically starts playing. VLC has nothing to do with it. As I mentioned, I've tried on several PC's: all the same result. The PC's with VLC, VLC is updated/current. Thinking it might be the VLC player I first tried to disable it in the settings...when I had the same issues, I uninstalled it completely. but no matter what I do, the animation homepage doesn't play.

Got it. If reloading the Bing home page doesn't help get the video going, could you try Firefox's Safe Mode? That's a standard diagnostic tool to bypass interference by extensions (and some custom settings). More info: Diagnose Firefox issues using Troubleshoot Mode.

You can restart Firefox in Safe Mode using

Help > Restart with Add-ons Disabled

In the dialog, click "Start in Safe Mode" (not Reset)

Any difference?

Yup, tried that already. Same result. I've even tried to uninstall firefox and reinstall firefox...but that doesn't help either. For the heck of it, I tried messing with the security settings and that didn't work... now I selected "reset" to put everything back to the original way. But no matter what I do, it seems Firefox won't run the .ogg/.ogv file extension?

I think you said Firefox plays the video when you load it directly, so the problem seems to be something about the way it is inserted into the Bing home page.

When I look at the HTML source of that page, the video tag does not have the URL of the video:

<video id="vid" onended="VM.play();" loop autobuffer preload="auto" oncontextmenu="return false"/>

That apparently is filled in by a script. If you right-click the video area and choose Inspect Element (Q), does your <video> tag have the URL filled in? (See screen shot attached)