sound card makes mouth popping noise...
Hard to describe the sound, but it's the sound you make when you roll the tongue and brush it against the palate (roof of your mouth).
I have set system sound scheme to none.
Realtek High Definition Audio. Everest tells me that the model number is ALC887.
This is the driver installed: 18.104.22.16841
It's Windows 7.
Edit: it's not the "tsk" sound!
Edit: Dell XPS 8300 desktop - i7 - h67 motherboard - do you need more information?