Have you tried updating your browser version so if it had an audio bug it fixed it?
If I get this right, you can play video games and etc but when you try to use anything that involves sound in your browser it doesn't work?
I'm having issues with sound, even after tryin most of the driver updates, and other frequent problems with vista sound. I can hear sound when I'm playing a video game, but not on the internet, media player, or while tryin to listen to music. Just started doing this after a vista auto update.