There are many kinds of antivirus systems that you can download or purchase for the security of your computer. While most commercial software that you can purchase comes with warranties and full customer support, many users also prefer the flexibility of free antivirus systems that can be downloaded from the creator's website or a download forum.

The best antivirus systems come with at least three basic features to enhance the security of your computer system, irrespective of whether they are free or purchased. Firstly, a good antivirus system ensures that it receives updates on a regular basis so that it can keep itself up to date on the latest detected threats.

Such updates should preferably be conducted at least once every day, and require access to the internet. Secondly, the best kind of antivirus system also has a scanning function that allows you to monitor the content on your hard drives for potentially unsafe elements. The program should ideally allow you to schedule daily or weekly scans according to your preferences.