I think the answer is that you are using a router and ICS doesn't work, nor should you want to use it, with a router. Let the router do the DHCP. Set both machines to get their IP address automagically via DHCP from the router. Uninstall ICS. Now the router should be your gateway (192.168.1.1 or whatever the Belkin default subnet is) and the machines will be whatever the Belkin assigns them on the same subnet. They will both have Internet access.
If you want to share files between the two machines, make sure you have an account with a password on the ME box (even if you use TweakUI to automatically log in) and that you create the same account and password on the Win2k box. Use Client for Microsoft Networks on the ME box. You don't need NetBEUI, only TCP/IP.
Malke