windows 2000 problem

I have a windows 2000 server and windows xp sp2 client machines. This problem comes only in one client machine. The problem is that only administrator of domain can log onto machine and when domain user tries to login message comes “the local policy of this computer does not permit you to logon interactively”
I have checked the local security policy under administrative tools.The option log on locally is disablled, not matter if i login thru local administrator or domain administrator.
Secondly in windows 2000 server when we check entire network the list of computer that are login to domain is visible , if one of the computer goes offline the list under domain name still shows the computer and doesnt refresh automatically untill we restart the server.
Please help in this regard
Thanks