I was playing some video on YouTube in Chrome a few hours ago, while multitasking several other things at the same time. I don't remember what happened precisely, but at some point, the YouTube video stopped making sound. I didn't pay much attention to it as I was busy doing something else, but now I realize that I can't turn the sound back on.
I originally thought it's a Chrome problem, but after checking around, I realized that Windows 7 keeps auto-muting Chrome. All my other programs (including VLC and Firefox) can play sound normally, but the Chrome channel in the Win7 Volume Mixer is set to mute. If I unmute it, the sound would come back on for a split second and then gets muted again.
I've also tried running Chrome in incognito mode, with all extensions disabled. The problem persists, though.
I have no clue why it's doing this. I've tried uninstalling and reinstalling the sound driver with no result. Any idea how to fix this?