Internet Explorer running on Startup

I support about 100 PC’s, all running NT4.0 Workstation. On several of these machines (over half), when I log on as the local administrator, Internet Explorer (5.1) starts up automatically. Now, it never actaully connects (to a web page), until IE is shut down and restarted, but I want to know why it is starting up in the first place!

It is just like it is running from the startup folder of a profile, but there are no shortcuts in any of the profiles (including All users), and it is not partof any scripts.

Recently, the same problem is occurring to a number of users around the office, and I’m stumped as to how to fix it.

Thanks in advance.