I'm not clear on what the issue is here. You want them BOTH logged onto
the same machine at the same time? If user A was logged on and now user
B has logged on hasn't user A effectively logged off?
I guess to answer your question, no. I don't know of any way you could
have user B logged into a Windows 2000 machine without User A logging off.
You can run certain programs as a different user with the "Run As" option,
but that's only going to apply to that specific instance of that program.