Now you might want to disable the firewall if user want to make troubleshoot any applications that do not function as expected behind a firewall.
Firewall is software or hardware that checks information that comes from the Internet or from a network. Then, the firewalleither blocks the information or lets the information pass through to your computer.Whether information is blocked or passed throughdepends on your firewall settings. A firewall can help prevent malicious software (such as worms) from gaining access to your computer through a network or the Internet. A firewall can also help stop your computer from sending malicious software to other computers. Windows XP, Windows XP Service Pack 2 (SP2), and Windows XP Service Pack 3 (SP3) include firewall software.
1. Go to start to enable firewall
2. control panel
3. network and Internet connections
4. network connections to enable firewall
5.open windows firewall
6. to enable firewall in second way ,right click on your Internet connection and select 'properties'.
7. Go to the 'Advanced' tab and check the 'Internet Connection Firewall' box.
What you have just done above is enabled firewall. Your computer will now record which applications on your computer attempt to access the Internet, and examine all incoming data against these records. Any unsolicited data will be dropped.
article source:http://www.checkcomputersetup.com/windows_xp/how_to_enable_the_firewall.html