Windows 11 includes Microsoft Defender Antivirus, which many users overlook. Manual virus scans are important due to evolving cyber threats, and a tutorial exists for conducting a full scan in 12 steps, taking about 45 minutes for setup. Users should confirm that Microsoft Defender is active and can automate scans with a script. Fake antivirus alerts can appear as browser notifications, and users should not follow their instructions. If a fake alert occurs, users should close it and run a quick scan through Windows Security. Common pitfalls in virus scanning include running multiple antivirus programs, scanning with outdated definitions, and initiating scans from pop-ups. Advanced security strategies include using Windows Sandbox and monitoring startup items. Regular scans are recommended, with a quick scan weekly and a full scan monthly. Microsoft Defender may be sufficient for many users, but additional protection may be necessary if other tools frequently identify missed threats. In case of a confirmed infection, users should disconnect from the network, change passwords, and report the incident.