Netbeui protocol no longer in Win2000

We have just upgraded our WinNT 4.0 to Win2000 but found out that the Netbeui protocol is no longer installed. The effect is that we could not see/browse the other workgroups in the network, and users who log-in to this server being the primary domain could no longer see the other workgroups aside from this workgroup.
How can we browse the Network Neighborhood similar to when we still have the Netbeui protocol in WinNT 4.0?
Thank you.