I did what you said and still cant hear the sound on web pages and windows.
If I try playing one of the sounds in the sound scheme windows default, I get an error saying:"Windows can not play the sound file %SystemRoot\media\windows xp Start wav. The sound card is already in use."
I can only play these sounds if I open them with windows media player or winamp.
Once I did get the sound back in my windows when I disabled my Unimodem Half Duplex device but if i tried to run any other audio files I got an error. X_X