Windows Firewall, first provided with Windows XP SP2, is provided so systems running Windows XP will be secure, when setup out of the box. One of the features of Windows Firewall is default blocking of file shares, so the bad guys on the Internet can't see the shared data on your computer.
Unfortunately, a secure system set up out of the box, and plugged in to your network, won't be able to provide shared data to the other computers on your network either. So you may have to configure Windows Firewall, to allow your computer to be accessed by the other computers on your network.
- Open Security Center from Control Panel.
- Select Windows Firewall.
- On the General tab, sake sure Windows Firewall is ON, and clear the selection for "Don't allow exceptions".
- On the Exceptions tab, enable File and Printer Sharing.
- With File and Printer Sharing highlighted, select Edit. If the Scope does not show as "Subnet", hit "Change scope" and select "My network (subnet) only".
- Hit OK as necessary.
If problems persist, continue with Your Personal Firewall..., and then Irregularities In Workgroup Visibility.