First let's be clear that web scripts absolutely can un-mute a PC. You can see the code at:
But this doesn't mean it's spyware.
Are you armed to the teeth in this area? I use WOT (web of trust) and AdBlock+.
Just a wondering... I always keep my Windows computer muted for the most part, but lately it seems to unmute all by itself, curiously when some advertisement video pops up. Is this a new tactic of spyware??