Sort of...

Firefox doesn't have a master mute button per tab or window. Instead, any volume control would be on the player, either the built-in audio/video player or a plugin-based audio/video/game player (e.g., Flash). So you should be able to manually mute the players you don't want to hear.

Are you finding that the muting crosses between the players?

On Windows XP you only have one main volume control setting, so you would need a special program that allows a more precise control of the volume.

There is this program for Windows XP, but it is a payed program and not free.

• IndieVolume is a per-application volume control for Windows XP
  http://www.indievolume.com/

It works per application according to the description, so you would probably need to a different browser to listen to the music.

They're not really players. I like to listen to either a streaming radio station or Pandora. Whatever game I play (basic, nothing fancy, like Pop Cap or PCH Games) has commercials between sections. I THINK I've tried all combinations of muting available in XP, and I either hear both or neither. If FireFox had a muting in the browser window, I could mute one and listen to the other.

Your only option would be if you can disable the sound in those games.

Did you look for a setting to disable the sound in the games?

Do those games use a plugin in Firefox?

Most of the games have sound muting, but the commercials cannot be muted. I guess there's no way to mute one browser but not the other.

Thank you both for trying!