I have had to reload Ubuntu and noticed something strange.
I can play MP3s in Amerok, I can play videos in Totem but in YouTube, after installing flash, I can see the movie, but no sound whatsoever comes out.
Also if this helps, I have noticed in YouTube there is no picture until I click on the area where the picture should be. The movie then appears but no sound.
I have checked sound, nothing appears to be in Mute.
Can anyone help here?