Have you set up port forwarding, using your static IP address? Try changing ports. In LW tools > options > advanced > firewall config. Change LW's listening port to 64049 > Apply > ok. You'll also have to forward this port number within your router. Remember that LW's listening port, port in the 'manual port forward' box & port forwarded within the router all have to be the same number.

Does LW connect on your Dad's XP computer?

Can you find out who your ISP is (who you pay for internet access)?

Did you make sure that your Norton firewall was allowing LW? If you go back to the link I left in my first post, you'll see instructions for Norton 2007. This link might help, as well.
http://www.gnutellaforums.com/226610-post6.html