In addition to the binary file isapi_redirect.dll, IIS needs configuration information that's really just a bunch of text files. This is typically created by wsconfig.exe when you set up the connector. The text files tell IIS how to talk to CF via the DLL - what CF instance, what port it's on, etc.
Generally, the way you set this up is to install CF on the IIS server, then just turn CF off. You could then remove most of the CF install manually if you really wanted to, but you'd obviously have to leave the text files themselves, which will be in a "wsconfig" folder if I recall correctly. I don't have an IIS-connected version of CF in front of me to verify this, but it should be easy to find. If you have multiple IIS virtual servers, and CF connected to each one individually, you'll see a bunch of subdirectories in wsconfig: wsconfig\1, wsconfig\2, etc. Otherwise you'll just have "wsconfig\1". Again, I'm working from memory here, but it should be close enough.
Dave Watts, Eidolon LLC