Stephen, Try removing the Logitech Mouse Software from MSCONFIG (Start Button -> Run, Type in MSCONFIG, Click Startup tab, uncheck anything having to do with the mouse).
This should help the problem.. also check for newer audio card drivers.. also go to Start -> Settings -> Cotrol Panel -> Sound and Audio Settings,
Make sure to click Advanced at the bottom under Speaker Settings and set the speakers to match your config.. if you are using 2 speakers with Woofer, use the standard Desktop Speakers setting..., click the Performance Tab and make sure everything is set to Max and click OK...
Next click the Advanced tab again under the Device Volume section, Click Options and put a check into Advanced Controls.. then click Options again and select Properties and put a check mark into every option listed..
Next in the main UI, put checks into Mute for Microphone, Line-In, S-PDIF=In, and Auxillary.. then click Advanced under Microphone and make sure Boost is unchecked.
Under Midi, if you have an Advanced button, click it then uncheck Reverb and Chorus, and click OK,
Under Playback, click Advanced and set your base and trebble for your comfortabler level.. this should most likely be either all the way down or up to the first marker... any higher usually distorts music badly.
Also adjust your Volum levels as you wish them to be set..
Also in here you can determine whether you want to use Digital output or not.. depends on if your speakers are rated for Digital playback or not.
Close these windows out until you get back to Sounds and Audio Devices Properties box.. Click the Speaker Volume button and turn them all the way up (this is the system setting for the speakers, not your physical volume control nob).. this will increase your PC's ability to put out high decible music at your command
Then click Apply and OK..
then try your software again after rebooting and see if you still get the humming.