NT 4.0, Terminal Server Edition is a separate product, so Terminal
Services is not a service that you can install on a normal NT 4.0
Server, you'll have to install TSE from scratch.
Windows 2000 Pro has no TS or Remote Desktop functionality at all
(except that it can be a client).
If you are looking for remote administration features, you'll have to
use PCanywhere or VNC on these systems.