I have a soundblaster so I open the Creative mixer and choose "what you hear" by clicking on the icon, over the record slider, that brings up the drop down menu.
Whatever card you have, you should have a help file with it. Open it up and search for "what you hear" and it should tell you how to set it up.
if u dont have "what you hear" then you will need a audio cable and join up line out to line in, once you have setup recording levels etc.
i use adobe audition (used to be cool edit pro) its the dogs dagglies program, in fact its a bit over the top really fror recording web streams but the editing is soooo easy, it should be available in the usual places.