Microsoft Security Essentials (MSE) - a free antivirus program that protects your computer from malicious software. It helps protect against viruses, spyware and other malware.
Users of Windows 7, Windows Vista and Windows 8 and above can download it for free.
It has all the modern anti-virus technologies, such as signature-based scan, the heuristic analysis and cloud security mechanisms.
Microsoft Security Essentials antivirus updates regularly. It works in the background and schedules antivirus scans whenever the computer is idle.