Recently I had to swop out my motherboard but kept everything else. I then reinstalled windows 7 (new install), installed WiFi, downloaded from windows update, downloaded AMD catalyst control centre & associated drivers for my gfx card.
I then plugged in my Logitech 2.1 speakers which seemed to be accepted by windows according to device manager. Tried the sound test but got nothing. You can see the green volume bar rise & fall.
Installed the Realtek HD drivers and got the same result. No errors either.
For both though I had to set front panel connector to AC97 from HD audio because it was erroneously detecting something every few seconds when nothing was being connected.
I have tried the speakers elsewhere, they are in good working condition & were fine when the previous mono was in place.