A vital weapon in your arsenal should be the firewall. This is necessary for preventing others from entering you machine. Hackers try to infiltrate systems in order to steal data or damage the system, or else they may try to take advantage of a computer by using it remotely for sending spam email (known as a "spam zombie"). A firewall is vital for protecting the system against these threats. If you are using Windows XP, you may already be acquainted with the built-in version (available on both Home or Professional Editions). However there are also many other options, of which Zone Alarm Free Firewall offers the best alternative.

A firewall is an important protection against this menace, and can be composed of hardware, software or both. A firewall serves as a partition, protecting your computer from the outside world, be it the Internet, a network or Intranet. Windows XP users already have this option which is automatically deployed on the system (verify that Service Pack 2 is installed, as this ensures that the firewall is implemented properly). Users of earlier Windows versions can purchase or download for free software equivalent firewall programs.