>In Win NT I can add users to a group using UsrToGrp.exe, how can I remove users from a group (programatically, even with RUN)?

Hmm, I could have sworn I wrote an article on how to do this with ADSI. I don't know how to do it via RUN, but you can do it with ADSI:

ox=GETOBJECT("WinNT://mydomain/mycomputer/Administrators")
ox.delete("myuser")

Disclaimer: haven't tried this, but it should work.