If youre listening to streaming audio you press the Record button (Red one) and on the Drop down box for the source you select Stereo Mix - this should do it - once youve finished recording you go to the File - Export as Wav a, Save as whatever you want to call it and theres your file which you keep - theres also a Save as mp3 option, but this requiresadditional add-ins.Any problems please let us know.
Cheers
Forgot to say that you can also record Non-streaming audio through media player doing exactly the same as above.
(Files on your hard drive, or CD's for example)
Cheers