NT 4.0 does not see the network.

The network was completly relocated to another building. (small network: NT 4.0 Server with 4 client stations.) The client stations can see each other peer to peer but the sever cannot bee seen, nor can it see the clients. A ping from the server to it’s own IP address indicates the NIC is ok. All protocal’s seem to be intack. Pings to or from the client stations time out. It is a ComPaq Pro Linear 800 server. Any advice or suggestions would be greatly appreciated.