Logon Script

hi,
I’m running a winnt4.0 enviornment w/95&98 clients. I have a logon script running that will map them to there home directory and a couple of other stuff. I hope this does not sound to odd. But is it possible to run a script for when a user logs off..You see, I made a registry change,that part of the logon script refers to, but when this one particular user logs off I would like this registry change to be put back the way it was. For the next user who logs on, who ever it might be….
Thank You