Everyone needs antivirus and antispyware software, but not everyone wants to pay for them. The for-pay versions are the best, but some of the free security software is great, too—and some is terrible. We tell you which is which.

With the vast number of viruses, spyware, and other malware served up alongside Internet content, there's no question that everybody needs security software. The problem is, not everybody can cough up the cash to buy that protection. Luckily, there's plenty of free antivirus software available, running the gamut from impressive products like Panda Cloud Antivirus to stinkers like digital defender free 2.0. There's a lot of work going on in the free antivirus space: Since my last big-picture piece in this category six months ago, I've reviewed updates for three of the products I'd looked at earlier, and I've examined three additional entries in the field. What follows is a survey of the best (and worst) of the free security software I've reviewed, with a select few of the better paid applications and suites for comparison.

The Commercial Advantage
Don't get me wrong; if you can scrape up the money, you get better protection from high-end commercial antivirus. Spyware Doctor with AntiVirus 2010 retains the honor of Editors' Choice for standalone malware protection and Norton Internet Security 2010 is our Editors' Choice for security suite. I use the Norton suite on my own systems, but I know others have a big hate-on for Norton. If you're in the anti-Norton camp consider BitDefender Internet Security 2010 or ZoneAlarm Extreme Security 2010 for suite protection.

Free Contenders
Some of the free options come pretty close to those top commercial products. Panda Cloud Antivirus Free Edition 1.1 does an even better job than the commercial products at keeping malware from infesting a clean system, though it's not as good at cleaning up malware that's already on board. The free edition of Malwarebytes' Anti-Malware 1.46 does a good cleanup job, particularly against scareware, and because it doesn't have a real-time antivirus component it gets along well with others.

Like Malwarebytes, Trend Micro's HouseCall 7.1 offers malware cleanup but not realtime protection. Like Panda Cloud Antivirus HouseCall uses signatures "in the cloud" rather than maintaining a local signature database. That means no time spent updating the database and no disk space devoted to storing it—very nice!

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AVG Anti-Virus Free Edition 9.0, Avira AntiVir Personal 10 and avast! Free Antivirus 5.0 live in the shadow of full-fledged non-free editions. AVG adds more protection to distinguish the paid edition from the free. The other two include all protective features, so unless you intend commercial use you'll do fine with the free editions. Avast! in particular tested well for malware removal, edging out Microsoft Security Essentials 1.0 for the best malware removal score by a free product using last year's malware samples.

Free Can Be Costly
Just because a product is free doesn't mean it will save you money, though. Installing a free product that lets malware steal your credit card number could be costly. IObit Security 360 performed poorly in almost every test except blocking and removing scareware. Immunet Protect Free 2.0 offers an innovative community focus that aims to keep you protected by protecting everyone you interact with. Unfortunately, its performance in testing showed that the protection it aims to share needs more work. digital defender free 2.0 also performed poorly, as did its for-pay sibling digital defender Pro 2.0.

Experiment!
If you buy a security tool and later decide you don't like it, you're stuck, at least until it's time to renew. Not so with a free product. You're free to play around, try different choices, and choose the one you like best. You can even experiment with multiple free products, as long as you're careful not to run real-time malware protection from two at once—that can cause problems as they're likely to fight each other. Whatever you decide, the important thing is to use something. An unprotected computer is dangerous to you and to everyone you contact—so get some protection. An empty wallet is no excuse!

The blurbs below provide brief thumbnail sketches of our much longer, fully tested reviews. Click through to the links to read the full reviews. Note that the blurbs below do not represent all our AV reviews, paid or free—just the ones who are good (or bad) enough to merit inclusion in this roundup. Check out our full complement of reviews at PCMag.com's security landing page.

• Malware Blocking (chart)
• Malware Removal (chart)

Free Products Mentioned in this Article

avast! Free Antivirus 5.0

Free
You won't recognize the latest version of the free avast! antivirus. It looks completely different and it's got more power under the hood as well.

Avira AntiVir Personal 10

Free
Avira AntiVir Personal does a great job keeping malware from infesting your clean computer system. Just don't rely on it to clean things up if the system is already infested. In testing, even when it did detect entrenched threats it often couldn't remove them.

AVG Anti-Virus Free Edition 9.0

Free
Version 9.0 of AVG's free anti-virus cleans up malware and prevents further infestations. This edition works faster and adds identity theft recovery.

digital defender free 2.0

Free
DSEC Software's digital defender free 2.0 doesn't cost money, but using it will cost you in limited malware protection.

Immunet Protect Free 2.0

Free
This cloud-based free antivirus aims to ensure that your whole community is virus-free, but it needs to improve its core protective abilities.

Trend Micro HouseCall 7.1

Free
Once a browser add-in, Trend Micro's venerable HouseCall is now a standalone thin client that keeps its malware-detecting intelligence in the cloud.

IObit Security 360

Free
IObit Security 360 installs and scans quickly. The problem is, it just doesn't do the job of removing malware or preventing malware installation.

Malwarebytes' Anti-Malware 1.46

Free
The free Malwarebytes utility is super-fast to download, install, and scan. Use it any time your regular security program hits a snag.

Microsoft Security Essentials 1.0

Free
Installing the free Microsoft Security Essentials will protect your system from malware—to a degree. But you'll get better protection from one of the other well-known free anti-malware products.

Panda Cloud Antivirus Free Edition 1.1

Free
The latest Panda Cloud Antivirus is the best free antivirus and antispyware software we've tested.

Non-free products mentioned in this article

BitDefender Internet Security 2010

$69.95
BitDefender offers everything you expect in a suite and more. It's especially good at malware detection and offers better antispam, parental controls, and privacy protection than most suites. It affects performance more than some, but it's a very good choice for all-around protection.

digital defender Pro 2.0

$25.00 Direct
Digital defender Pro takes a lot longer to scan for malware than its free edition, but it does an equally poor job and costs more.

Norton Internet Security 2010

$69.99 Direct
Utilizing innovative technologies that crank up your PC's protection without bogging down its performance, Norton Internet Security 2010 remains the best overall security suite on the market.

Spyware Doctor with AntiVirus 2010

$39.95 direct
Spyware Doctor with AntiVirus 2010 adds numerous new "guards" against malware and promises enhanced malware detection and cleanup—and delivers. This product, our new Editors' Choice, broke records in my malware-removal and malware-blocking tests.

ZoneAlarm Extreme Security 2010

$69.99 Direct
ZoneAlarm Extreme Security 2010 boasts impressive features, including full-disk encryption. But it slows performance, installing it is torture, and its anti-malware scores are only so-so. It's still a good product, but I'm not quite as thrilled with it as I was last year.