Also, depending on how your speakers are connected, check if the "Digital Output Only" box is checked or not....
Right click on the speaker icon in the task bar, Open Volume Control, and go Advanced
(or from Control Panel >Sound and Audio Devices>
click on the Advanced button from Device volume>...then Advanced from the new window...)
Clear the box if you went with an 2 or 3 wired connection, or check the box if you hooked up via one digital cable connect...
but that depends on you Logitech speakers...if you went with the Z5500, definitely check digital output...
You might need to update your audio drivers, found
here