Just got a new mic, logitech G930 and sound and mic works cuz I can talk to my friend but videos and games dont have any sound … :S
look on your soundmixer for the browser sound level
Its using that flashplayer thing, so either you got it setup wrong,
or your mic is still muted on your sound card or something like that :D.
I suggest you try deinstalling the unity flash player, and reinstall it.
You should get a message about sound ingame, on the first start up you make after reinstalling it.