PC Tools Antivirus Free Edition

And while the app purports to protect against Trojan horses, a common malware type, it detected only 46 percent of such software in AV-Test.org tests. It did better in detecting worms, but its catch rate of 83 percent for the self-spreading malware still didn't compare with the detection results we saw from Avira AntiVir Personal, the overall leader among the free antivirus software we tested.

Unsurprisingly, the poor performance carried over to AV-Test.org's heuristic tests, which use two- and four-week-old signature databases to simulate how an app will handle new and unknown malware. PC Tools Antivirus came in last, with respective results of 33 percent and 36 percent (in contrast, Avira, the best app we tested, scored 52 percent and 45 percent, respectively). It was decent in detecting and removing existing infections, missing only one out of ten--but most of the tested antivirus apps got them all.

While the program installs smoothly and looks relatively good, it doesn't schedule a scan by default, nor does it automatically update. The software will notify you once a day (by default) if an update is available, but to make it do the updating by itself, you will need to turn on the Smart Update feature.

In short, there's no reason to choose PC Tools Antivirus when other free apps can truly keep your PC safe. Fortunately, the behavior-based PC Tools Threatfire supplemental utility is as good as Antivirus Free Edition is bad.