I think what you are looking for is Remote Desktop. First you have to make sure it is enabled. The default is disabled so go to MY COMPUTER, right click and PROPERTIES. Click on the REMOTE tab and enable REMOTE DESKTOP. Now you have to find out what your IP is. If you have a firewall just check it (usually at 192.168.1.1) and then go to another computer, which is not in your house and using the same internet connection. For example go to the computer at work, open remote desktop (which is installed automatically on windows xp). If it is an older windows version, download it here: http://www.microsoft.com/windowsxp/downloads/tools/rdclientdl.mspx. Open the program anyways and put in your IP. It should connect and you login like you usually would. Your computer at home has to be on and online. For security purposes create a restricted account if doing that, just in case somebody ever see your username and password. Make sure the IP stays the same it changes. Good luck!
I understand that it is possible to set up my Windows XP PC, so that I can access and control it remotely. How is this set up? Do I need to set up a user name and password from the PC, so that there is some level of security when I later attempt to connect from a remote location?