limit local domain logon to a single user

I'd like to limit domain logon on a particular computer to only the user(s) that I allow to logon from that location.  Does someone know the most efficient way to do this from within active directory? Or even point me to the article or KB that will help out?
On off-days, other office personnel are logging into a particular network computer with alternate logins.  This activity is valid as far as network permissions go, but are keeping the home worker from being able to easily login from her home office location.  I'd like to limit login to the one main user of the computer (and a couple other administrators, if possible), and prevent all other users from being able to login at all, even iff they power-down and restart the computer.
thanks