Previously, I've been using Avira or AVG antivirus as my first choice for free antivirus software. But for some serious antivirus protection or virus removal, my preferred professional and paid antivirus software would be McAfee antivirus.
Although this might be old news already, new kid in the antivirus block and also the maker of virus infested Windows operating system had released their very own antivirus software called Microsoft Security Essentials. I think it's about time too. Who else would know their software better than Microsoft themselves, right?. The free Microsoft Security Essentials antivirus provides real-time protection for your PC that guards against viruses, spyware, and other malicious software. Security Essentials also runs quietly and efficiently in the background so that you are free to use your Windows-based PC the way you want—without interruptions or long computer wait times.
But here's the catch. Microsoft Security Essentials requires a PC running genuine Windows software. If you own a non-genuine Windows copy on your PC, don't even think about it. This software will run a genuine validation process first before installation and if you are silly enough to run this on a pirated copy of Windows you'll be rewarded with the dreaded WGA notification on your desktop. Oh and one more thing, Microsoft Security Essentials only run on Windows XP and above.
Head on to their official website to download one.