Is the problem with embedded YouTube videos on those sites, or videos that have no relation to YouTube?

Some videos do use other players, such as Windows Media player. If you right-click the non-playing video, can you tell which plugin is being used?

Also, could you give URLs to some problem pages so we can check out what's going on?

The YouTube.com and embedded YouTube videos play fine so I think they are videos that have no relation to YouTube.

When I right-click on the non playing video I get a Flash local and global settings dialog box along with the Flash version.

Here is a URL of a video that doesn't load or play: http://www.bloomberg.com/video/92290395-nissan-s-590k-bespoke-porsche-killer.html

Thank you for your help.

There is a "pre-roll" ad on the video. Do you use any ad-blocking add-ons? If so, can you try turning them off temporarily or making an exception?

Also, the video appears to require scripts from ooyala.com and gotraffic.net in order to run. If you are using NoScript, check for blocked scripts from those domains.

I already tried disabling Adblock. I'm not using NoScript. Is that something I need?

Everything was fine until about 2 weeks ago but I don't know of anything I did to change the set-up.

Anybody have any helpful ideas?

In case the problem is an out-of-sync file in your cache, you could try clearing it.

orange Firefox button or Tools menu > Options > Advanced

On the Network mini-tab > Offline Storage : "Clear Now"

Since the Flash player is involved, you could try clearing some locally stored "Flash cookies" and see whether that makes any difference.

Depending on your version of Flash, you may have a specific Flash Player control panel with your other Windows control panels. This allows you to clear some or all of your Flash cookies.

Start > Settings > Control Panel > Flash Player

On the Storage tab, there are buttons to view storage use by site and to simply Delete all. If you play Flash games, you might not want to delete all but instead selectively clear storage for ooyala.com and gotraffic.net, if any.

There is a similar dialog available by right-clicking the Flash player and choosing Global Settings (assuming you are visiting a site where the player is working). Or alternately you can use this page: http://www.macromedia.com/support/documentation/en/flashplayer/help/settings_manager07.html

Any luck?

No luck. I tried the suggestions and still no videos except for YouTube type videos.BTW, I have the latest version of Flash and it tests ok.

Clear the cache and the cookies from sites that cause problems.

"Clear the Cache":

• Tools > Options > Advanced > Network > Offline Storage (Cache): "Clear Now"

"Remove Cookies" from sites causing problems:

• Tools > Options > Privacy > Cookies: "Show Cookies"

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance/Themes).

• Don't make any changes on the Safe mode start window.
• https://support.mozilla.org/kb/Safe+Mode

• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

That fixed it! Thank both of you for your help.