Did you check if the video player has a volume button that isn't set to mute the sound?

Clear the cache and cookies only from websites that cause problems.

"Clear the Cache":

• Firefox/Tools > Options > Advanced > Network > Cached Web Content: "Clear Now"

"Remove Cookies" from sites causing problems:

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

See also:

• https://support.mozilla.org/kb/Video+or+audio+does+not+play
• http://kb.mozillazine.org/Video_or_audio_does_not_play

Sometimes, the video or audio content in a web page cannot be properly downloaded and displayed in Firefox. A required plugin may be missing, outdated, blocked, in conflict with another plugin or extension, or the content may be blocked for some reason.

The volume is not muted. I cleared the cache. Any other ideas?

I assume that the videos play and that only the sound isn't present, is that correct?

Did you check the volume icon on the Windows Task bar?

You can also check for problems with Flash local storage (some sites store the sound level in a Flash cookie).

• Windows Control Panel > Flash Player > Storage: Local Storage Settings

Flash Website Storage Settings panel:

• http://www.macromedia.com/support/documentation/en/flashplayer/help/settings_manager07.html

Global Storage Settings Panel:

• http://www.macromedia.com/support/documentation/en/flashplayer/help/settings_manager03.html

Yes, the videos play, but no sound. I did all things mentioned above, still no sound.

You can check for problems with current Flash plugin versions and try these:

• disable a possible RealPlayer Browser Record Plugin extension for Firefox and update the RealPlayer if installed
• disable protected mode in the Flash plugin (Flash 11.3+ on Windows Vista and later)
• disable hardware acceleration in the Flash plugin

• http://kb.mozillazine.org/Flash#Troubleshooting

I did this and found I have the most current version of flash and it's working. To see if the Flash plugin is working and what version is being used, visit one of these pages:  http://www.adobe.com/software/flash/about/  http://helpx.adobe.com/flash-player/kb/find-version-flash-player.html

I disabled the hardware acceleration in the Flash plugin and that did not help.

Can you give me some more detail on #1 realtime player and #2 disable protected mode, mentioned above?

Did you check the details as listed in the above linked mozillaZine knowledge base article?

• http://kb.mozillazine.org/Flash#Troubleshooting