Whether it's browser hijackers grabbing your search page, or the latest ransomware encrypting all your files, every PC needs a sterling antivirus package to keep threats at bay.
Don't rely on Microsoft's very own Windows Defender to keep you safe. Sure, it's free and easy to use, but independent tests show its protection rates regularly dip below 90%, compared to 99.x% for the leading competition.
This doesn't mean you have to start spending big money. Opting for a free solution doesn't have to mean compromising your security – there are some great freebie tools around.
Don't automatically rule out paid products, though. Commercial packages often (although not always) deliver the best protection, and sometimes include extras like password managers, web filtering, antiphishing tech and more. If you're looking for the maximum security, at least consider parting with some cash.
Avast free antivirus
A great security freeware
Browse the lengthy feature list of Avast Free Antivirus and it might sound complex: antivirus, password auditing, a secure browser, software updater, network vulnerability checker, and more.
Fortunately, the program bundles everything into its 'Smart Scan'. Launch this with one click and you'll soon get a report listing any malware it has uncovered, software patches you're missing, potentially risky browser add-ons, weak or duplicate passwords, and more.
The top testing labs give mixed results for Avast Free's antivirus protection, rating it anything from excellent to mid-range. We've found it reliable, but a little more consistency in large-scale reviews would be welcome.
Where they do agree is on performance, with just about everyone saying the package has little impact on your PC's speed.
There are stronger products around, but if you're interested in its extra features, or want something that won't slow you down, give Avast Free Antivirus a try.
Opt for the Avira Pro Antivirus though and you get a few extra features like background, automatic software update and a proper Data Shredder.
AVG Antivirus Free
AVG - now owned by Avast - has struggled to keep up with the competition in the past few years, but don't rule out the company entirely – its latest engine is showing real signs of improvement.
Independent lab AV-Comparatives has consistently rated AVG in the top 10 for its Real-World Protection test. AV-Test has recently found it offers above average protection rates, with few false positives.
The free edition only provides the core antivirus and web protection basics, but it does have builds for Android and Mac, as well as Windows. Even better, you can remotely manage all your devices from a web console.
There are some issues. In particular, AVG AntiVirus Free doesn't get priority real-time updates, leaving you a little more vulnerable to the latest threats.
Just remember that Avast purchased AVG in July but we've been told that it is business as usual for now.
But you can fix this by buying the commercial release, paying extra adds an enhanced firewall, free support and anti spam functionality. Both products are solid, reliable, and the best AVG releases for a while.
Avira Free Antivirus
Security without the add-ons
At first glance, Avira Free Antivirus doesn't look like the best security choice. The interface is dated and relatively complex, there's a distinct shortage of extras, and even basic web protection requires installing a separate browser add-on.
The package scores where it matters, though, with all the big testing labs – AV-Comparatives, AV-Test and Virus Bulletin – giving it stellar ratings, comparable to high-end competitors like Bitdefender and Kaspersky.
Avira Free is easier to use than it looks, too. The program can take care of most threats all on its own, and if you do need any assistance then a capable local help file explains everything you need to know.
You do get some bonus features, including a simplified interface to help you make use of the Windows firewall, and autorun blocking to reduce the risk from infected USB keys.
The package is also very lightweight. AV-Comparatives' April 2016 performance test placed Avira first out of 19 for having the least performance impact on a PC.
Overall, it's not flashy – there's no touch-friendly interface or HD icons here – but for value and pure desktop protection Avira Free Antivirus is hard to beat.
You also get Laplink PCMover Express, DriveLock Private, SuperEasy Driver Updater and Avira Antivirus Pro for Android thrown in.
BitDefender Antivirus Plus 2016
Recommended for multi-year, multi-users
In a world packed with free security software, Bitdefender Antivirus Plus 2016's annual £29.95 fee may look expensive. But there are discounts available – a 3-device, 3-year licence costs £89.95 – and you do get a lot for your money.
Bitdefender's engine is one of the most accurate and reliable around, for instance, loved by all the big independent testers.
Web filtering blocks access to malicious sites, a secure browser keeps your online financial transactions safe, and there's a password manager which auto-completes credit card details in web forms.
An excellent antiphishing module alerts you to malicious links in your search engine results, and blocks access to dangerous sites.
There are one or two issues – the anti-ransomware module offers good all-round protection, but sometimes blocks legitimate programs – but Bitdefender Antivirus Plus 2016 is still a likeable package which offers excellent detection rates, great performance, and more than enough bonus features to justify its premium price.
Alternatively, you can purchase the Total Security 2016 edition for not much more. It adds a firewall, parental control, antispam, file encryption and much more!
F-Secure Antivirus 2016
For slower computers
If you're tired of the junk that weighs down some antivirus tools, F-Secure Anti-Virus will make a refreshing change. There are no unnecessary extras here, no bonus features you'll never use: you just get straightforward real-time browsing and antivirus protection.
Keeping things simple doesn't mean compromising your safety. The package typically receives maximum marks for protection from AV-Test, and generally scores highly with AV-Comparatives, too. They also say it can generate significantly more false positives than most of the competition, but how that affects you will vary depending on how you use your computer.
The interface is a major plus. It's extremely easy to use, lightweight, and for the most part you can just leave it alone to look after your PC. The program has minimal effect on your system performance, and if you do need to intervene then you can generally solve any issues in a couple of clicks.
Competitors like Bitdefender and Kaspersky offer better protection and more features, but F-Secure Anti-Virus remains a likeable package: fast, lightweight, and able to run alongside many other security tools without conflict. It's one of the better value commercial products, too.
Kaspersky Antivirus 2016
A great all-rounder
Kaspersky Anti-Virus 2016 is a stripped-back security package which focuses on the core security essentials: web filtering blocks dangerous URLs, an accurate antivirus engine detects and removes threats, smart monitoring technologies track and reverse malicious actions, and that's about it.
Fortunately, what you do get works well. Very, very well. We've consistently found Kaspersky to be amongst the best at blocking malware, and removing it from an infected system, and it's regularly top-rated at sites like AV-Comparatives.
The high price could be an issue. If you're looking for better value, check Kaspersky's Internet Security products. These are often discounted, and you could get a much more powerful suite for around £5 more.
But if you're just after accurate, reliable and consistent malware protection, Kaspersky Anti-Virus 2016 will serve you well.
For better, more rounded protection, Kaspersky also has 2016 edition of its Total Security Multi Device product which covers three devices (PC, Android and Mac) for a full year. Although it is a tad more expensive, it offers privacy protection, secure storage and synchronisation of your passwords and files as well.
Norton Security Standard
A jack-of-all-trade package
Norton Security Standard is one of the most comprehensive packages here, combining antivirus, browsing protection, a firewall, password manager and more.
One of Norton's strongest areas is preventing you from getting infected in the first place. An excellent URL blocker does a good job of keeping you away from malicious websites, and the program won't allow you to run files it doesn't trust.
This can be infuriating if you're always downloading and trying out the latest freeware, as it'll always be raising alerts, but if you're trying to protect a largely stable system – your kids' laptop, say – then it can be very effective.
The product isn't widely tested by the main labs, but AV-Test scores Norton highly for its reliable and effective protection.
The price is also high, unfortunately – £29.99 for year one, £39.99 per year after that – but Norton Security Deluxe may offer better value: spend £10 more from year two and you're covered for up to 5 PCs, Macs, tablets and smartphones.
Norton Security 3.0 (version 2016) costs only a tad more at Amazon for the 5-device, 1-year subscription. For a small premium, you can double the number of devices supported and you also get 25GB of online backup bundled with a 100% refund assurance.
Panda Antivirus 2016
A security veteran gets an upgrade
Opting for free antivirus can mean you'll pay in some respects. Panda Free Antivirus will change your browser home and search pages unless you notice and clear a checkbox, it installs a browser toolbar for URL blocking, you must register with your email address, and the interface is always suggesting: 'Upgrade to PRO!'
Still, once you're up and running, there are plenty of compensations. The program looks good, is easy to use, and has reliable URL blocking to keep you away from malicious sites. AV-Test scores Panda highly for protection, and even if something does penetrate your defences, a bootable Rescue Kit environment will help you get rid of it.
Factor in other bonus extras, like the configurable interface (right click tiles to optionally remove them, Windows 8/10-style), and you'll see why Panda Free Antivirus 2016 is a likable and effective tool.
Although Panda Antivirus Free is a superb deal, you can get the Global Protection (2016 edition) version (which includes Mac protection, VIP services, chat support as well as identity and family protection) for five computers for not a lot of money at Amazon.
Trend Micro Antivirus+ Security
A strong contender
Trend Micro Antivirus+ Security is a capable antivirus package that's easy to use with above average antispam and brand new ransomware protection.
How good is it? The top testing labs all rate it highly for protection, but after that there's little agreement. AV-Comparatives says it gives a high number of false positives, and slows down your PC more than just about anything else; AV-Test reports few false positives and excellent performance results.
Our experiences with the product are mostly favourable: protection levels appear similar to Bitdefender, false positives are only marginally higher, and it doesn't slow down our system noticeably more than anything else.
We'd recommending running the trial for its full 30 days before you buy, then, to see if you notice any problems. But if you're unaffected, its high levels of detection and excellent bonus features make Trend Micro Antivirus+ Security a good choice.
Trend Micro Maximum Security 10 (2016 edition) is probably the cheapest antivirus on the market for the 1-year, 3-device version (you only get the product key) or you could get a better deal from Amazon with Internet Security 2016 which is a one-year subscription for three devices for not much more.
Webroot SecurityAnywhere Antivirus
Just about every antivirus tool claims to be lightweight, but Webroot SecureAnywhere AntiVirus is the only one to really deliver on this front. Installation takes seconds, the program files barely grab 2MB of your hard drive, RAM footprint is tiny, and there are no bulky signature updates to tie up your bandwidth.
There's no compromise on features, though. Along with the core antivirus protection, there's smart behaviour monitoring, accurate real-time antiphishing, a firewall and network connection monitor, enhanced anti-ransomware, and other interesting extras.
It's not easy to compare Webroot's accuracy with the competition, as the big testing labs rarely test the company's products. But when they are reviewed, they generally score well, and our own tests show solid and reliable protection.
There's a lot to like about SecureAnywhere AntiVirus, and Webroot's 70-day 100% money-back guarantee suggests it's confident in the product, too. If you're tired of bloated antivirus engines, Webroot must be on your shortlist.
Webroot SecurityAnywhere Antivirus comes with a money-back guarantee as well as 25GB of online backup. This is the 3-device pack that contains a card only (you will have to download the actual product, either for Windows or for Mac, and activate it).