network slow

hi all
i have 5 computers.one server[using windows 2000 server] and 4 clients [windows xp and 2000 pro].I created my server as domain controller.ip=192.168.0.100, gateway 192.168.0.100, and preffered dns 192.168.0.100
and also created four user accounts with password.ok . while im trying to log on from clients it will take a long time.4 minutes. pls answer me any solutions..