refmon :
There is no software available for this product.
http://www.logitech.com/en-ca/support/speakers-z130?crid=409§ion=downloads
'Speakers' don't need software drivers.
How is the sound playing through the monitor? HDMI? Unhook the audio from HDMI, and make it go out through the back audio port.
Settings, Control Panel, Hardware and Sound, Sound|Manage audio devices