No audio in FireFox or IE

Hello,
I have no sound on the internet, when I use firefox or IE to watch a youtube video, I get NO AUDIO.

I have checked the volume on the computer, on the played, I get sound with itunes.. so I don't know what the problem is.
I have tried several solutions listed on the net, including:
installing newest java and adobe flash things
and, one this about copying a bunch of coding into the registery.
NOTHING WORKS
I have rebooted after all these installs too.

I am using Vista, and I am trying to get sound out of the Firefox 3 Beta 2.

PLZ HELP