Win 7 Browsers doesnt play sounds

I just bought new computer and started it normally everything was installed already, i dl Firefox and go youtube but sounds doesnt work, when i test with IE doesnt work either.

Sounds work fine with Realtek test and with media player, but browsers doesnt play any sounds.

Im using Windows Vista and Firefox 3.6.2

I tried the registry fix thing mentioned in this "forum" but not working. I have also checked the volumes in vista sound volume option for different softwares.

nothing seems to work =(