This happens for every 1 in 3 or 1 in 4 videos I open in YouTube. They are switched to mute by default, and it means I have to click on the unmute symbol in YouTube, and then the sounds works just fine. Then when I reopen the same video later on, it might not be switched to mute. I have cleared my browser cache in Internet Explorer, and can't find anything Flash related which might be causing the problem. What is the deal?