Worth checking if the Windows XP Firewall is on. You may have Firewall software and so in fact have two Firewalls running. This is not nessesary and could slow things down. Turn off the Windows XP Firewall and leave your other Firewall software running. (If you don't have your own Firewall software, search out Zone Alarm and install this.)
To check if the Windows XP Firewall is on .....
Find your Network Connection Icon.
Right click on it and select Properties.
Go to the Advanced Tab.
You'll find a checkbox in a frame called "Internet Connection Firewall" - deselect this checkbox to turn off the Windows XP Firewall.
Click okay.
John Wilson, April 2004