Windows 2000 Logon troubles.

A user can not logon to his laptop with his ID either locally (workstation only) or with a network connection (domain).

The user’s id/pw, Administrator id/pw, and Guest id/pw were tried both locally and connected to the network.

I beleive the problem occured after a LAN admin
at another location (may another domain) logged into the laptop (as Administrator?) and proceded to try to sychronize a Notes database which failed and upon reboot, the user was unable to logon and I beleive so was the LAN admin.

Any ideas / suggestions? How can a local Administrator id/pw be recovered?