" ...........sounds like speakers underwater, both on speakers & headphones no matter what program I am running...."
Check the settings and preferences for your sound card. There's usually an icon in Control Panel for it. As an example, the "Realtek HD Audio Manager" has a range of sound-effect presets and one of them is called "Under Water". See if you can find something similar.
It is odd though that you say the same problem occurs in Windows 8 too (if that's what you mean by "W8").