User accounts on NT/W98 network.

We have a network consisting of an NT4 server and several W98 workstations. I am able to create domain user accounts at the server and log on at the workstations with these accounts. However when I log on at the workstations using different user accounts they all have access to the same My Documents folder on the hard drive of that workstation. How do I give each user they’re own desktop? I would appreciate any help.