Avast Free Antivirus
Avast's freebie finished second in PCWorld's 2012 free antivirus roundup. Avast Free Antivirus 7 mostly excelled in protecting against malware, it has a versatile interface, and it sped through our battery of malware tests.
Avast's defenses were weakest at blocking new real-world threats: It caught just 78.6 percent of them--not outstanding, but slightly above average. Avast did far better at stopping well-known malware, detecting 99.1 percent of samples in our zoo test--a very good showing. This package cleans up malware infections effectively, as well. It detected all the malware residing on our test PC, and disarmed the invaders 93 percent of the time, tying for second-best in this test. The utility also removed all traces of infections two-thirds of the time.
The Avast offering won’t slow your PC down much. It completed the on-demand scan test in 1 minute, 34 seconds, for second-best in the group; and it finished the on-access test in 4 minutes, 16 seconds, good enough for third-best.
Avast's interface has a lot going on; advanced users will find many settings to toggle. Despite this complexity, it is nevertheless friendly enough that it shouldn't scare away less-geeky users.