Asus M4A3000E motherboard
Onboard Sound
Windows 7 Home Premium
Rear Panel connector to Stereo Speakers in Monitor

Sound suddenly ceased to emit from speakers. Have checked all the likely suspects, no 'mute buttons' selected etcetera.
In Windows Sound/Playback with Media Player on a repeat loop there is evidence of sound transmitted to the speakers, ie bars lighting green. On selecting 'Configure/Stereo'
no sounds are heard when testing individual speakers (Top two on the schematic) However, if Quad sound is selected, sound can be heard from both speakers when the bottom two on the schematic are selected for test. If left configured for Quad sound there is still zero output from Media Player.
Any clues warmly welcomed!
 
Hmmm. Downloaded the latest Via software from the Asus site as you suggested, but to no avail. So I used setup to uninstall, and when I restarted the machine it was working fine! Don't need the fancy Audio Control Centre so I'll leave well alone... Thanks for the nudge in the right direction...