Windows 98 and AD

I have several windows 98 workstations (used for students), which connect to
a W2K domain. I have set up a profile for the the users and occasionally it
happens that, if an user logs on the profile is corrupted. I then have to
log on as an administrator to remove the profile and rebuild it to get
things working again.
The profile is stored both locally and on the server. I would like to use a
policy where the profile is always loaded from the server nad nothing is
stored locally. How can I accomplish this?

Regards
Laurens Bouhuijzen