The word "essential" denotes something of absolute necessity--something that you can't get by without. But Webroot Internet Security Essentials 2011 ($60 for one year, three PCs, as of 12/2/2010) is sadly a bit of a misnomer: Its antimalware performance proved it was simply not up to the task of securing a modern PC. If you want "essential" protection, you'll need to look elsewhere.

Webroot's overall performance landed it in a distant last place among the 13 applications we tested. It had one bright spot: it fully blocked 22 out of 25 real-world malware attacks, and partially blocked the remaining three attacks. But in every other category we tested it fell short. Its known-malware detection rating of 93.2 percent isn't the worst we've seen, but it's still below average compared to the other suites we tested. False positives were also a problem, particularly when we scanned an already-infected machine: Here, Webroot's dynamic malware detection engine (which detects malware based on how it behaves) identified a whopping 20 percent of our safe yet questionable sample files as malware.

Its impact on overall system performance is miserable: At on-demand scanning, Webroot was the slowest of all 13 apps, and at on-access scanning it wasn't much better, landing 12th out of 13 for scans that run when files are opened or saved. System slowdown with Webroot running was also a problem, landing the app at ninth place. On the plus side, Webroot put forth a modestly good 70 percent rating at scrubbing active malware components from infected systems.

Webroot is at least a simple application to get around in. Designed for the rank novice, its main interface offers only a handful of options, with big and bold graphics to let you know if your system is (theoretically) protected. Video tutorials are available to hold your hand, if needed, and the company makes it easy to find additional support via prominent placement of web help links and an 800 number support line.

That might come in handy if you happen to overlook Webroot's tendency to automate its decision making for you. For example, its integrated firewall is set by default to block incoming connections if you don't override the decision within a couple of minutes. If you've gone for a cup of coffee during that time, Webroot could create a big problem on your home network where none existed before.

Webroot is very easy to use, and we appreciate the application's extras, including a secure online backup tool and hard drive scrubber (which deletes temporary junk and cache files to save space). But none of that really matters if the application isn't keeping you safe.