Software Tool : 360 Total Security Free Antivirus
License : Freemium / Ad-supported

360 Total Security is Free Antivirus with lots of features included. Virus detection signature engines keeps on updating in regular basis, can be utilized to monitor system health. Real Time detection of spyware, trojans, backdoor, virus and smart blocking their execution on operating system makes 360 total security antivirus a award winning product. 

(link sends you to official author site)