USB Headset on XPS 8900

I have a brand new, just out of the box XPS 8900.  The odd thing is, the headset microphone only works when the Sound options window is open.  Close that window, and the headset/mic stops working.  If it's open it works perfectly.  Since I use the headset/mic for work, I'd love to know what's causing this.  It's strange, to say the least,

EDIT:  This machine is running Windows 7 (yes I know, it came that way).