Multiple Logins

Why do individual Windows 2000 Professional work stations show as multiple logins on an NT 4.0 server? Even a work station with only one user shows as three separate and distinct logins, using three of the licenses we have. Another work station has two user names with one for local and one for network access. This work station shows up as eight distinct logins using up another eight of the licenses we have.

With only a ten user NT license, these new work stations can really lock up the system.

Why does this happen when only one user ID is being logged in?

Thanks,
Ande