Windows Defender is a free security program from Microsoft that helps protect your computer from online threats such as spyware, viruses, and other malicious software. It provides real-time protection against a wide range of malicious threats, including those that try to take control of your system, compromise your data, or steal your identity. Windows Defender also monitors your system to ensure that it remains secure, and it automatically alerts you if it finds suspicious activity. Additionally, Windows Defender can help you identify and remove any malicious programs that may already be installed on your computer.
Discontinued. The program is currently unavailable on the official website: the download option was removed in early 2017. The latest version, 1.0.3.9, released in December 2014, can still be downloaded from Wayback Machine.