Volume control Settings

Im a Network Administrator. We have 11 servers ( windows
2000 server ) and 219 clients ( windows 98 ). In windows
98 when we start the system the volume control settings
disables automatically.I would remove the sound card
drivers and restart . And again install the drivers , it
gets enabled.But after 2 or 3 days the same problem
persists . It occurs with all the different sound cards
and with many systems ( repeated systems ).Please give me
a permanent solution , as soon as possible.
Thank you.