Our cyber-security lab captures and analyses hundreds of thousands of brand-new viruses every day to bring you assessments on dozens of antivirus packages - and that includes Windows' built-in security.
Windows Defender comes as standard with Windows 10, so you might well be wondering if you need to invest in a premium package or even switch things up with a free alternative.
We can help you decide if Windows' own tools are secure enough to combat modern malware, or if alternative free or paid software is a safer bet - or worth it for some useful additional features.
There has always been a big question mark hanging over Windows Defender (part of what's now called Windows Security) and whether it's enough to keep your computer safe. Our tests show that in some circumstances, it's an effective partner for keeping you safe online, but in others there's need for improvement.
First, the good: its Smart Screen technology is very effective at blocking malware that tries to start running on your computer. There is a caveat to this, though; it's only effective when your computer has an internet connection because it sends tiny fingerprints of suspect programs to its online database to see if it matches known threats. Without an internet connection, it can't do this and therefore doesn't have much to go on when choosing whether to block a program.
It's also effective at blocking phishing attacks, although only in the Edge web browser. If you use another browser, you won't get the added protection of Windows' own phishing protection if you happen to end up on a scam website trying to steal your data. Not only is Edge an effective anti-phishing tool, it actually beats both Google Chrome and comes in just a smidge behind Mozilla Firefox when it comes to thwarting phishing attacks, according to our lab tests.
That's not to say it can't be enhanced by using antivirus software; we found several antivirus packages that were more effective than Edge at stopping phishing attempts.
Our has all the details, and if you suspect you're not getting the level of protection you need, there are plenty of free and paid-for alternatives that have next to no impact on the speed of your computer and will provide additional protection.
If you're interested in shopping around, we've tested a wide range of free and paid-for software to help you choose. Here are some of the recent highlights.
F-Secure is known for its corporate IT security solutions, but the Finnish firm also offers software for both PCs and Macs.
Bitdefender is one of the biggest antivirus engines in the world, powering a range of different packages alongside Bitdefender's own. You can get the paid-for Bitdefender Internet Security package, or the free software. Just like Kaspersky, Bitdefender covers Macs, too.
ESET has managed Best Buy status several times over the past few years, but our tests change and get tougher with each passing year, so previous success is not an indicator of effectiveness today.
Norton, which has rebranded to Norton Lifelock, is a well-known antivirus brand. It doesn't offer a free antivirus service, instead it markets its 360 Security Deluxe package for both PC and Mac users. It isn't the cheapest software to buy, so make sure you shop around for the best deal.
Kaspersky is one of the best-known brands of computer security, and it has both free and paid-for products for both Windows and Mac computers.
Our antivirus test is seriously tough. Around the world we operate what are called 'honeypots' - think of these like digital fishing nets designed to capture thousands of strains of murky malware and viruses. Our honeypots capture up to 400,000 files every day, adding up to 146 million infected files over a year.
Each package is hit with more than 10,000 samples of malware,including more than 700 samples of ransomware. We assess how well the packages deal with the threats while the computer is online and offline, too.
We penalise antivirus packages that pester you with messages, or wrongly zap a file that you actually want to use. Plus, we test every single menu, control and feature to ensure that a package is simple to install and use - and to uninstall should you want to switch.