Best antivirus software

Which programs offer the best protection?

Kaspersky Anti-Virus 2009 (*Est. $35) scans all Internet traffic in real time to block viruses before they are saved to disk. It monitors all processes and registry changes, warning users about suspicious modifications. The program is capable of implementing a system restore if a disaster strikes, but Windows XP and Vista also have that feature. It also protects against keyloggers, phishing and malware sites, and it comes with free technical support.

Kaspersky earned CNet.com Editor's Choice award two years in a row, but reviewer Robert Vamosi says the 2009 version "did not impress us enough to extend that run another year." Although there are some nominal improvements, the latest release loses points for cumbersome installation, system glitches and a "clunky" interface. Overall, though, Kaspersky is still a solid contender. Vamosi says the problems with this year's release are mostly confined to ease of use and that the actual level of virus protection is consistent with previous versions.

User reviews for this program tend to be highly polarized. CNet readers give it an overall rating of only 2.5 stars, but about half award it a perfect or near-perfect score. The biggest complaints concern Kaspersky's free customer support, which one user calls "terrible, rude, and completely lost." Some owners also report lock-ups and compatibility issues. CNet.com contributors do tend to be rough on antivirus programs in general, though. The one exception is NOD32 9 (*est. $35), which gets exceptionally good feedback.

Kaspersky antivirus software produced mixed -- but generally very good -- results in independent lab tests. Kaspersky successfully prevented 97.95 percent of viruses in a test by Virus.gr, a Greek antivirus-testing lab, but it was less than perfect in a couple of Virus Bulletin's tests, and thus failed to achieve full certification from the organization

Like Kaspersky Anti-Virus, ESET NOD32 Antivirus 4 (*est. $35) protects against viruses, spyware, adware and phishing attacks. NOD32 uses a single engine to scan for all malware. It blocks infected files from being opened. The company's claim that "it has the smallest footprint and fastest performance" may be exaggeration, but reviews say that it does very well in those regards.

Previously, NOD 32 was widely considered to be the best all-around antivirus program, with one exception, a poor user interface. That problem was largely rectified in last year's version 3.0, with CNet.com's Robert Vamosi saying NOD32 "finally gets its interface right." The user interface now has two options: standard and advanced. The advanced menu offers complete user control, and much of the terminology is in plain English, but the default settings seem to be designed well enough that users may be able to gain the full benefit of the program without ever opening the interface window.

The latest version, NOD32 Antivirus 4, adds a number of usability enhancements. Information pop ups are hidden when using full-screen applications, like games or presentations, for example. There's also a battery mode that extends laptop battery life without reducing protection. On the security side, there's scanning of SSL-encrypted channels, such as HTTPS and support for additional e-mail clients.

No professional reviewers have weighed in on the latest version, which emerged from beta just as our update went to press. However, blogger Michael Aulia tested an early beta version of the software and came away impressed with all aspects. The best news is that, in keeping with NOD32 tradition, impact on system performance -- even in the beta version -- was essentially non-existent. The handful of user reports we've seen indicate that NOD32 Antivirus 4 continues to be a top choice. NOD32 antivirus software is certified by all the major testing labs.

Experts agree that antivirus, anti-spyware and firewall applications are essential. Yet, many of the otherwise best antivirus programs are incompatible with anti-spyware and firewall programs made by other companies. But by all accounts, NOD32 antivirus software works and plays well with all other software.

Norton AntiVirus 2009 ( *Est. $20) is the top-selling program overall. It's popular because it is effective at detecting and blocking viruses, spyware and worms. It's also aggressively marketed, and retailers frequently offer free-after-rebate promotions. Reviewers say that Symantec (the company that published Norton software) has done a good job of streamlining its once-bloated security programs. CNet's Robert Vamosi calls the 2009 version "slimmed-down and faster" than previous releases. He's not impressed by Symantec's technical support, though he does give them kudos for dropping their "over inflated per-call pricing schemes."

Owner ratings at CNet are a bit lower than those of the site's editors (a common occurrence with software reviews), but Norton's aggregate user score is still a respectable three out of five. User feedback is highly polarized. About half say that it's fast and reliable, but the rest report system drag and poor tech support. For those still running Windows XP, there seem to be some issues with compatibility. Users are a little bit happier at Amazon.com, where the program earns a good four out of five star rating, though a significant minority still reports problems. It's as if owners are running two different programs: one that's light and intuitive, and another that causes system lock-ups.

Other antivirus software

CA Anti-Virus 2009 (*Est. $25) gets a below-average ranking from TopTenReviews.com due to its limited feature set and its tendency to bog down system performance. CNet hasn't yet covered this year's version of the standalone antivirus software, but Robert Vamosi said of last year's release that it "isn't up to speed with the competition," and users gave it abysmal one-half star. The same goes for this year's CA Internet Security Suite 2009 (*Est. $40), which includes the antivirus program. Owners complain of system lock-up and incompatibility, and Vamosi criticizes its "uninspiring interface" and "sluggish performance."

Panda Anti-virus Pro 2009 (*Est. $20) does a bit better than CA's product on professional reviews, but ratings are consistently mediocre. CNet hasn't covered the latest release, but Vamosi said last year that he couldn't recommend the 2008 version. His assessment of the latest Panda Internet Security 2009 (*Est. $35) is that it's "vastly improved in speed and effectiveness over last year, but could use a little more work on specific features and technical support."

F-Secure Anti-Virus 2009 (*est. $65) might be worth considering. The program and its Internet Security sibling have received some favorable reviews in the past couple of years despite some ongoing issues with resource drain. We didn't find any user reviews of F-Secure Anti-Virus 2009.

ZoneAlarm Antivirus (*Est. $30) adds virus scanning and some advanced firewall controls to the company's free basic personal firewall. We didn't find any professional reviews, but the average user rating at Download.com is a respectable 3.5 stars out of five.

AVG Anti-Virus 8.5 (*est. $35) offers the same basic virus scanning as their free edition (discussed below), but it adds rootkit detection, as well as screening for downloads and instant messages. Version 8.5 is similar to Version 8.0, but adds more sophisticated behavior-based virus detection. It also protects against exploits, which can allow malicious users to take advantage of system vulnerabilities when you visit an affected website.

Robert Vamosi reviews version 8.0 and calls AVG Anti-Virus "solid at finding and removing viruses and spyware as well as blocking web threats," but says that it's resource intensive and somewhat lacking in technical support. User reviews are mixed: CNet's average user rating is an abysmal 1.5 out of five, but at Download.com, the software scores a more respectable 3.5 stars. At Newegg.com, a version packaged with anti-spyware protection garners four out of five, and more than 70 percent of owners give it a perfect rating.