This problem started a while ago, perhaps 3-4 weeks. Maybe more or less. Lets say I am playing a youtube video with sound. I then remove my headphones (sound normally still plays, sometimes not). I then plug my headphones back in (ANY firefox sound no longer works, even without headphones in). I have to end the firefox process and restart it to play sound again. I do not have this problem with internet explorer. I have tried uninstalling firefox/flash and reinstalling them removing registry entries and left over files before doing so. When firefox sound has stopped working, other sound from IE or my computer still works both with/with out headphones. Firefox will even play sound through the computer while other applications play sound through the headphones if I restart firefox with out music playing. I will be changing to another browser if I can't fix this problem. Firefox was the perfect browser for me, but as recent versions came out. There were more crashes, issues and I am quickly not liking it. Thanks in advance I am using firefox 3.6 at the moment without problem