I am using Windows Controller to perform a shutdown on remote computers. This is performed by invoking the command through .Net remoting through a Windows XP service running on the remote PC.

This works perfectly unless the remote system is not logged on.

The remote PC's are headless systems that are not typically logged in.

Any idea why this is not working? I suspect privalage problems.

Permissions may be the issue. Try impersonation in your code to see if it works.