network problem

I have w2k server running active dir-and dns..and have problem with xp pc that gives no signes of problem when signing on domain but when I try broswe network gets error cant find servers or not accessable. I can ping server with ip address or server name.. from server I can see the pc but cant brose to it either.. please help.. if do nslookup i get cant find server .. non exixtant domain.. same error on both..