Re: Acer aspire 6920G - Sound problems - Ubuntu
It's a long shot, but right-click on the volume control icon, select Preferences and try selecting something other than Master to control.
I had a laptop where Master did nothing, but one of the other selections worked - can't remember which, but it may have been Headphones.
Before you criticise someone, walk a mile in their shoes. Then, when you do criticise them, you're a mile away and have their shoes.