I'm on Windows XP SP2 with no hack for concurrent sessions installed. I want to simply execute a single command on this machine from another remote computer, and nothing else. I want to run it as either the user who's already logged in, or as a different user. I have administrator permission. The command will not be GUI-based, and I don't want to install a software on either host or client.
The client is running Linux (preferred), but I could also use Windows XP.
My major concern is that the user currently logged in should not be logged off.