does the sound device still show up in control panel/multimedia applet?
Run sfc, run drwatson.
I had a problem once, in 98se or WinME, where the soundcard would install and function perfectly until I rebooted, then it would be gone....actually drwatson told me the answer...turns out that somehow the "mmsystem.dll" was not loaded in my system.ini.
There should be a line like this--> drivers=mmsystem.dll power.drv
and probably also this--> sound.drv=mmsound.drv
Drwatson told me that without the mmsystem.dll my multimedia would be "erratic"..hehe.
JP