Green Bar in Volume Control is Moving, No Sound

I have speakers plugged in to my computer running Windows 7 Home Premium 64Bit. The computer is recognizing that I have speakers plugged in and when I play something the green bar moves with the music. However, no sound is coming from the speakers. I have gone into the BIOS settings and enabled onboard audio. All sliders are at their full volume. I have unplugged and replugged the speakers, rebooted, shut down, uninstalled and reinstalled the sound driver, all to no avail. I have eliminated the possibility of the speakers being broken by testing them with an iPod.

Any help is appreciated.

May be a "duh" but have you checked the headphone jack in front to see if you get sound there ??

right click the speaker icon on task bar and select playback devices, then select a soundcard as default playback device ,you may have to right click in the sound window that opens and click show disabled devices,hope this helps good luck.