If you use a router to connect to the Internet, you probably need to configure it to allow the Remote Desktop connection to your computer. For more information on routers and firewalls, see my Internet Firewalls column. You need to forward two ports to your Windows XP Professional-based computer: TCP port 3389, which Remote Desktop requires, and the port you specified in the TCP Port field in Internet Information Services (or TCP port 80 if you did not change the default).