A good antivirus program should protect you from all types of malware, including worms and Trojan horses. It should also be able detect and stop the spread of potentially unwanted software, which can change your browser settings or flood your screen with advertisements. Some premium antiviruses offer additional features, such as dark web monitoring, ID theft alerts and parental control.

If you’re using Windows Microsoft’s built-in malware protection, known as Windows Defender on older computers or Windows Security on more recent machines, does a decent job of keeping your computer safe. However it’s not as quick or efficient in detecting malware as standalone antivirus brands that regularly achieve high marks in independent lab tests. Additionally, it doesn’t come with any additional security tools such as password management software or other tools for other devices.

Bitdefender Antivirus Free Edition is the most effective antivirus for Windows based on malware prevention impact on the system, as well as ease of use. It is rated highly by the respected AV-Test labs and is simple to install and run. It offers protection for one PC at a very low cost, but for a few extra dollars you can have more comprehensive protection with Bitdefender Total Security and Antivirus Plus.

A good paid antivirus suite will usually include a lot of additional features. This can include a VPN, performance-optimization tools, and software for Mac OS, iOS, and Android. If you’re looking to stick to the basics and simply get the best malware protection, Sophos Home Premium is an excellent option. It offers some additional features at reasonable prices.