In order to gain access to your home computer this is what you need:

1. Your home computer must be turned on.
2. Your home computer must be connected to the Internet.
3. You must know your home computer IP address: you can open command prompt and type ipconfig /all then press Enter.
4. You must have Remote Desktop Connection client software on the home computer (it comes free with Windows XP and Windows Vista) - how to setup the home computer (the client):
Windows XP remote desktop

Once this is all done then you can make a remote desktop connection between the two computers. Please note that if you have a router at home it should be set to allow remote Desktop connection.