Malwarebytes by Malwarebyes Corporation. www.malwarebytes.org ONE of the BEST offering FREE version and the PRO/Purchased version is EXCELLENT as well. This program recently saved by bacon against a NASTY pest.. That avast!, Pest Patrol, Norton, McAfee's, AVG, and Kaspersky wouldn't touch. I run it about once a week on my primary box but run another program daily. I've got 20 years experience in the IT industry on Multiple platforms so have tried alot of these. Somethings I've learned about protection. ONE Protection at a TIME!! And never rely on just 1 program to keep your box CLEAN. Have a Weekly cleaner and then a different daily cleaner.