No sound in Safari, Firefox, etc

[SheerGold]

I have a G5 that is running OS 10.5.8.

There is no sound when a video is playing in a browser, for example Utube, GoogleVideo, etc. That is so with all the browsers - Safari, Firefox, Navigator, Wyzo, etc.

However the sound does play when playing a video under a normal video player - QuickTime Player, VLC, RealPlayer, etc.

Anyone have any suggestions?

 

[Gregg2]

Whenever this happens to me, I discover that I have muted the sound, or maybe it gets reset without my input, but I just hit the volume increase key and it comes back. Hope it's that simple!