No sound from the Internet

I have no sound fron the Internet. All other sound work properly (Window / Media Player, etc.)

I've explored all the other fixes listed, but to no avail. Even to the extent of reloading windows.

OS = Windows Vista / SP2

Dell XPS 630 (Svc Tag 9HDNZF1)

Firewall = Norton Internet Security 2012

IE = 9

Adobe Flash (current)

Java (current)

I've been trying all the KBs, forums and solicited solutions for 2 weeks and now I'm at my wits' end. Please assist.

Regards

Lacy Smith