At work, just for training purposes we set up a simple office network.

We have a server running Windows Server 2003.

We have 15 workstations running Windows XP. These workstations
are connected to a Catalyst 1900 switch via CAT 5 and the switch is
connected to the server via CAT 5 cable as well.

Everything was working smoothly, the users we created were able to log on
to our training domain.

We decided to change the IP address of the server to see what would happen.

We found that some users are able to log in with no problem.
Some users were able to log on but their mapped drives failed.
Some users can't log on at all.

So that's the scenario we got so far.

The question is how do we clear the DNS cache of all the old name-to-IP address
mappings on the clients workstation? (If that is the solution to our problem).