Avira Free Antivirus 2012 is fast and is unlikely to scare you with false-positive warnings about legitimate files, but it is also worse than average at detecting malware, and its interface is overly complicated.

When tested for PCWorld's April 2012 roundup of free antivirus software, Avira blocked 70.4 percent of the samples of new viruses in our real-world test, slightly worse than average for the tools we tested. It also lags in disinfection: Though it found all active malware infections on our test system, it disabled only 80 percent of them, another worse-than-average showing.

I'm not a big fan of Avira's interface. Its overview panel is better than in previous versions, but the interface remains too technical in places. Also, I noticed that Avira occasionally displays ads.

Avira's results weren't all bad, however. It detected 99.7 percent of known malware samples in our zoo test, and it was one of only two free antivirus programs we tested that didn' mistakenly label legitimate files as possible malware. Its on-demand scan time of 1 minute, 31 seconds was the best in our testing, and its on-access scan time of 4 minutes, 54 seconds was respectable.

Using Avira will by no means leave your PC completely open to malware, but you should consider the higher-scoring AVG Anti-Virus Free Edition, Avast! Free Antivirus 7, or Panda Cloud Antivirus 1.5 first.

--Nick Mediati