Many websites today allow you to download antivirus free of charge. If you think such programs cannot perform as well as the full version products, think again. Most types of these programs may not have the complete feature found in full versions, but they are still capable of providing basic protection for your computer, nonetheless. When deciding between demo versions and full versions, simply ask yourself which features are important to you. If you are after more advanced features, then you should opt for the full version. If you are only after basic protection for your computer, the demo version should be enough as long as you keep the software updated.