We have NT 4.0 workstation. In the administrator profile, all sound functions work fine, but in all user profiles, only MIDI files work. On attempting to play RealAudio, MP3 or WAV files, error messages come up like: Could not initialize audio. Cannot open the audio device. Another application may be using it. Driver not found etc. On trying to install another driver, it says the user profile does not have enough privileges, and on checking in the Administrator profile, it shows there ARE enough provileges for the user to install drivers. Any one have any idea what's happening?

First, add the users that want to install the drivers to the local administrators group in User manager. Second, check the hardware profiles for the user profile in which the drivers aren't working. It could be that the sound device is disabled in that profile. You can check this in the devices list - HW Profiles on the right hand side.