I had this problem.
It was among other problems that were corrected at the time, but my best remembrance is that we deleted the existing audio drivers and modem drivers as well as a free ISP service that was causing a problem connecting to the Inet.
After that we reinstalled the modem and selected the audio driver thru W2K.
Also dumped IE5.5 and went back to 5.0 (don't know if this is relevant).
Problem went away after this. Make sure that the device you installed is infact the active device being used (go to start,settings,computer and look at your devices. Your modem driver should be listed and no other.
When i get back to my computer at home, I have some notes and will let you know more precisely.