Program tries to install at every logon

I have a Windows NT Workstation 4.0 machine that launches a setup program for a screensaver each time a user logs on. It doesn’t matter if the
username is Administrator, a domain admin, or just a user, it always launches the same install program.
I have checked the Startup folder for each user, as well as the All Users and Default User profiles. I searched the registry, but was unable to find it. I am stumped, and don’t know how to stop it short of re-installing the
OS.

Any help is appreciated!