Independent labs including AV-Test, AV-Comparatives and Virus Bulletin regularly rate Qihoo 360 as one of the top two antivirus products. This isn't just some marketing gimmick, either. Install it and you can be protected by Bitdefender technology (an excellent commercial engine), Avira (probably the best of the free offerings), and two further engines of Qihoo's own. Still, what makes the suite interesting is that it uses no less than four antivirus engines. It's not always easy to operate, and if you run into problems there's no significant documentation to help. This feature overload does make for a relatively complex interface. It provides antiphishing support, online shopping protection, network threat blocking, hard drive clean-up tools, a Windows update checker, and more. If you're looking for a standalone antivirus package then 360 Total Security might seem a little overweight. So if you're tired of those annual subscriptions, read on – we've picked out five of the best free antivirus engines to deliver great security at no cost. However, there are plenty of free antivirus solutions around which do deliver solid protection, and are just as capable as their commercial cousins. Also check out: Best antivirus: 10 home security suites reviewed and rated.You could ditch your paid products and hope Windows Defender will keep you safe – but as independent testing shows very poor detection rates (it typically misses one threat in six), that's probably going to be a serious mistake.

But so do the security companies, which is why covering all your devices can become very expensive. Reliable antivirus protection is a must-have for every PC. Our best free antivirus round-up has been fully updated.

The best antivirus 2015 free