Users looking for a free antimalware product to protect themselves have long enjoyed Avira, which is available in a no-cost version for personal use, but which subjects you to a single daily pop-up urging you to buy the full suite.

Upgrading to the paid Avira AntiVir Premium Security Suite adds a passel of extra features--anti-spam, an included firewall, and parental controls, to name just a few--but the core malware detection and removal system is the same.

The Avira interface is a matter of personal taste. Some users will find its simplicity refreshing, while others may feel its lack of hand-holding and plain English explanations are off-putting. Avira offers two configuration systems: The standard mode should be plenty for most and provides more than enough tweakability. Or you can check the "Expert mode" box - easy to overlook - and delve into the minutiae of the software. Here's where Avira can really get obtuse, but unless you're really concerned about, say, limiting the size of Avira's log file, Expert mode has nothing that most users will need to worry about.

The good news is that Avira requires minimal to no extra configuration work in order to fully protect yourself: Avira's default settings will be absolutely fine for most users, and only if you find yourself needing to manually scan a file or your PC should you ever really need to open Avira's control panel at all.

The even better news is that, based on our testing, Avira does a top-notch job at keeping you safe and sound. Across the board, Avira turned in very good numbers, blocking 99.0 percent of known malware, and fully stopping 21 of 25 of real-world attacks (it partially blocked an additional 2 attacks). Avira is also quite fast at scanning. It was the second-fastest on-demand scanner and the fourth-fastest on-access scanner among the 13 applications we tested. That said, it put a bigger dent in overall system performance than most other suites.

We did encounter a couple of sore spots. While Avira did a very good job at disinfecting active malware components, it left behind more remnants (inert malware files, registry keys, and so forth) than many of the other suites we tested did. Avira also lost points in the realm of false positives: The software's dynamic malware detection engine (which identifies malware based on how it acts on your PC) blocked a full 10 percent of safe (yet suspicious) applications in our tests. In daily use, you can see Avira's overzealousness quite readily: It blocks just about every AutoRun application it encounters, whether on an optical disc or a thumb drive. Making matters worse, there's no readily apparent way to stop this behavior.

Though Avira is overall a competent and easy-to-use antimalware application that offers set-it-and-forget-it functionality, these issues lowered its score.