Just recently I have found when clicking on news stories that their advertisement and news videos start up automatically and that if I have set the speakers to mute that it overrides this. I then re-mute the speakers and a few seconds later it is overriden and the sound starts up again. I think this will be a growing common problem as it seems a "new trick" by hungry media sites. Can someone please let me know how to stop it happening?
Right-click on speaker icon in the system tray near the clock, select "Playback devices". Click on the default device (default is likely named "Speakers") and select "Properties". Click on the "Advanced" tab. Uncheck "Allow applications to take exclusive control of this device".