Network concerns need some ideas plz

My customer has a simple 8 user tcp/ip LAN network running w98se with a w2000 server. Here is the strange part, unable to browse the network from 1 system. This system has Internet access, able to ping other machines but no one in the network neighborhood. Switched out NIC’s w/o success. Verified network setting with another mach still nothing?
Any help would be great. thx