On the MSDN site for WTSSendMessage[^] look for this text: "WTSSendMessage to a remote computer is denied by default" and read what it says. Could this be your problem? > The problem with computers is that they do what you tell them to do and not what you want them to do. < > If it doesn't matter, it's antimatter.<

Immediate suggestions that come to mind: Try disabling any and all firewalls on both PCs. Check the RPC services are all enabled and started and functioning properly (You'll have to look these up.) Try some of the Microsoft samples first and see if they run without problem.