I had the same trouble as Karem7 because I did something to get my Logitech headphones to work through the USB port. I downloaded the drivers
and my sound now works through the front plug and the computer speakers but doesn't work through the USB port. When I go to the Control Panel and click on Sound I see Speakers and Dual Headphones, Independent Dual Headphones, SPDIF (Digital Out via HP Dock), and NVIDIA HDMI Output options but when I click on the Dual Headphones I can't get the computer to switch to this option. Any ideas??