Retrace your process from the beginning. I would take two of the PCs in the network and set one up as the Computer Browser host and the other as the client. Make sure you have then both on the same subnet, sharing options set to "Work/Home", firewall should be on, netbios settings to default, disable lmhosts for now, comment out the hosts file settings (because you want the client name to be found through netbios not hosts file). Remove the WINS server from the network. Reboot the the machines and test ping by address and name. Test nbtstat by address and name. If it all works, add the other machines. In the end, add the WINS server and modify the lmhosts configuration for your machines and retest. Somewhere along the line you might discover what went wrong if you can reproduce it. Last, you might have an issue with your dhcp server. Is your dhcp server another PCs or working through a router/switch.