Disable your XP firewall!!! Norton & XP firewall are known to conflict with each other. Besides, XP's firewall isn't so good. 1. Go to the control panel, double click on Windows Firewall, check the disable box.

2. * Configuring Norton Internet Security (click on link)

What brand & model of connection devices do you use? Birdy asked you about that, as it may be part of your problem.