Download Wallix Pro
Wallix Pro protects your computer by monitoring the traffic of your network and prevents hackers to damage or steal your personal information such as passwords and addresses. Recommended to be used with an anti virus of your preference.
It blocks unwanted connections and focuses in stop hackers from getting inside your system. It detects suspicions behavior of incoming files and alerts you immediately to proceed. It's not the most powerful firewall out there but it works and it does what it says.
This software is completely free and the new version improves its performance.
It's compatible with Windows Vista and XP.