Though the Windows firewall is good in Vista and Windows 7, many people still prefer to use a third party firewall to protect their computers. Note that using only a firewall without an antivirus will not help in securing your computer or network.
ZoneAlarm firewall is one of the best firewalls that I came across. Due to the ZoneAlarm firewall, I place the Comodo firewall at second place. My personal experience while dealing with both the firewalls has shown that ZoneAlarm is comparatively easy-to-use. The Comodo firewall is good, but is not very user friendly. For example, the Comodo firewall presents messages that are not easily understood by users who are not well-versed in the names of processes used by Windows.
ZoneAlarm, on the other hand, presents lighter messages that even a new user can understand. ZoneAlarm configures itself as soon as it is installed. It checks for all the important Windows processes running on your computer and allows them access to the Internet if required, instead of asking users who may get confused by the process names.
Click this security software download link for ZoneAlarm firewall to download it.
I hope this answers your queries about where to find free computer security software. If you have anything to add, please feel free to use the comment boxes below this article.