Sure I can;
I re-installed direct-x 9.0c (the latest version). Then, after running dxdiag (diagnosis program from Direct-x) I noticed the quartz.dll file (as stated in dxdiag) didn't have as much info as the rest of the direct-x files.
bts gave the next solution. This re-registers the quartz.dll file. That means it repairs its entry in the registry. You register the file by running (Start --> Run) the next line:
%windir%\system32\regsvr32 %windir%\system32\quartz.dll
It asks for your confirmation, and after that; the sound was back!
Hope I explained it clearly, otherwise let me know (and also please if it works out for you
)
Good Luck!
Chico