Microsoft Defender isn't bad, but it's not enough to fully protect your PC. You don't have to pay extra, though—just use one of the top free antivirus apps we've tested.

Use Windows Sandbox to safely install and test unknown apps in an isolated environment. Protect your PC from malware and risky software without affecting your system.

ZDNET tested the best antivirus software on the market, with support for multiple operating systems, VPNs, and robust protection.

You can spend money on third-party PC optimization tools to improve performance, but Microsoft PC Manager claims to deliver the same benefits for free. I put it to the test. I've been testing PC and ...