The sound on my computer isn't working...?

The sound on my computer has mysteriously quit functioning. I have three large Creative brand speakers and a Realtek Digital Audio Output. My sound card is working fine. I tested the speakers with the Realtek HD Audio Manager, and even reset them. The speakers work when I test them and they sound fine. The problem is, when I attempt to play any sound, it doesn't work. I turned on some music, then went to the control panel device center, which said that the digital output was working and the bars showed it was creating sound, but the speakers had no bars and weren't moving sound. I'm not sure what to do because I am more of a "html-internet nerd" than someone who knows how to fix devices. I'm pretty sure there has to be some kind of loss of connection between the Digital Output and the Speakers, but where...?