I had the same issue with my Creative 2.1 set-up only the issue was with the right speaker where you control the volume. The subwoofer worked, the left speaker worked but the right was garbled or with extrmely low volume.
I contacted Creative and did all their advice but nothing was resolved. Came to find out it was the jack on my subwoofer. If I moved it around the subwoofer would pop and become garbled with low sound output but the right speaker would then work.
I had to fiddle with the jack until all three worked and for 4 months now all is good. I just hope I don't have to move anything soon.