OK Firstly the PC you want to remote desktop has to be running XP Pro. The PC you want to connect from can be any windows OS but XP has the connection software built in, rest you'll need to go to microsoft.com > downloads > remote desktop software.
The PC you want to remote desktop:
1) Go to Control Panel > System > Remote Tab
2) Tick the remote desktop option, the main admin/ user account should be added to allowed users, you can edit this but you need to set a password!
3) You need to find the external IP. Go to
http://www.whatismyip.com/ and write down the address.
4) Go to Control Panel > Network Connections > Double Click Local Connection > Click Support Tab
5) Write down the IP Address (should be 192.168.0.X) and the Default Gateway address (should be something like 192.168.0.1)
6) With IE/ Firefox open http://<insert default gateway> e.g.
http://192.168.0.1
7) If it asks for a user and password, could try admin for both, or I hope you know the password!
8) Go to port forwarding and open 3389 for that IP you wrote down earlier,
NOT the default gateway IP!
9) Go to another machine outside the internal network, open remote desktop, connect to that external IP and hopefully it should work
