I'm Stumped: Firefox 3.0 Sound Doesn't Work

[dgood]

OK this is something that has plagued me for a while on and off. My girlfriends computer has Firefox 3.0 and her sound doesn't work on anything in it. I've uninstalled Firefox and Registry and other files and reinstalled it to no avail.
What I know:
1.) Sound works fine in IE 7
2.) She has Norton Antivirus and a toolbars on Firefox (i.e. google toolbar and norton toolbar.)
3.) I've updated or installed the newest verisons of Quicktime/Flashplayer/VLC/
4.) Can't watch Youtube or Quicktime or stream music for last.fm or any thing involving sound.

Any ideas? I'm stumped like I said.

[DMB2000uk]

Running vista with the app mixer set too low?

Try reinstalling the browser sound/video codecs.

Dan

[dgood]

oddly enough installing real player worked. I don't even ever use that program but for some reason it overrode something and fixed the problem so I guess that's that. I'd already tried installing vlc and reinstalling flash player.