Instructions for Activating Windows XP Internet Connect Firewall
1. Click on the Start button.

2. Click on Control Panel, then click Network Connections. Note: If you've installed Windows Service Pack 2 (SP2), the firewall is turned on by default, so you're good to go.

3. Right click on your internet connection and click on Properties at the bottom of the menu box that pops up.

4. In the Properties window that pops up, click on the Advanced Tab.

5. Near the top, under Internet Connection Firewall, click to check the box next to "Protect my computer and network by limiting or preventing access to this computer from the internet".

6. Click OK. The Windows Internet Connect Firewall is now protecting you from being hacked by anyone from the Net.

This is a temporary stop-gap measure until you can install a full fledged firewall.