I think it is just youtube videos (but it may have been other embedded videos, e.g. on the Real World Dailies site), but for the last 2 days, off and on, I have had no audio even though the videos play fine. I am using XP and Firefox. Any idea on what is causing this? My computer still makes its normal noises, e.g. when you click on stuff, but the video audio selectively plays. Thanks so much; I'll pick a best answer TODAY! Yes, definitely. I've tried even muting it, turning it back on, turning the volume down and then up again, etc. Then I'll just leave it alone for 10 minutes, hit play again, and it'll work on its own!!!!