[Every month I'll write an article related to getting quality free tools on the internet, which can improve your computing experience and give you peace of mind. Sorry Mac and Linux users, I'm only looking at Windows operating systems here.]

A firewall is an essential tool, and going onto the internet without one would be like going to war in your birthday suit, with no weapons or armour. Since Windows XP (Service Pack 2 and upwards), Microsoft has included a free basic firewall to protect you from security threats on the internet. In this article, I will look at and evaluate Microsoft's standard service but I will go into a lot more detail on stand-alone clients.

If you're in a hurry - here's how I rank the 5 that I've tested.

1. Comodo Internet Security
2. Online Armour Free
3. PC Tools Firewall +
4. Zone Alarm Free
5. Windows Firewall

Windows Firewall is your first line of defense, especially if you're not particularly computer literate and likely to plug your ethernet cable in without thinking twice about security or protection. Starting on a good point, Windows Firewall effectively eliminates that problem that we've all experienced - when you need to download a firewall but if you connect up to the internet, you are unsecured all the way up to the time it installs. On a bad point, Windows Firewall is a silent product that gives only the most basic protection which leaves you out to dry on key applications or connections that could harm your computer. I've actually found that, despite asking me in the background whether I want to unblock an application, it still lets me run it - as opposed to forcing the application to close.

Online Armour Free is a really good Firewall for those users that want to keep only certain areas of their computer at maximum security. The first thing I noticed with Online Armour free is the feature called "run safer". This feature allows users to set certain applications such as web browsers and e-mail to run with limited user privileges, making it harder for a hacker to take control of your PC. To further improve its user friendly features and keep you from doing too much, OAF gives you the option to automatically regard all applications on your computer as trusted and you can choose to scan for safe applications. The program guard features, which alert you, heavily depend on user interpretation and I can see this being quite a challenge for an average user. None the less, this is a great firewall that can offer a lot of protection for people who primarily browse the internet and use e-mail.