Microsoft Security Essentials

Microsoft Security Essentials (MSE) is a free antivirus software product created by Microsoft that provides protection against different types of malware such as computer virus, spyware, rootkitsand trojan horses for Windows XP (x86^[4]), Windows Vista, and Windows 7 (both x86 and x64). Microsoft Security Essentials replaces Windows Live OneCare, a commercial subscription-based antivirus service and the free Windows Defender, which only protected users from adware and spyware. Unlike the Microsoft Forefront family of enterprise-oriented security products, Microsoft Security Essentials is geared for consumer use.

Microsoft Security Essentials received positive reviews upon its release. As of September 2010, it has 30 million users.

Microsoft announced plans for a free consumer security product, codenamed Morro on 18 November 2008. It marked a change in Microsoft's consumer antivirus marketing strategy: Instead of offering a subscription-based antivirus with a host of other tools, such as backup and a personal firewall, Morro would be free for all genuine installations of Windows not intended for business use (with an exception for small home based businesses) and offers protection against all types of malware. Microsoft Forefront would be offered alongside Microsoft Security Essentials, with central management tools not present in Microsoft Security Essentials.

On 23 June 2009, Microsoft opened a public beta to 75,000 people in the United States, Israel, People's Republic of China and Brazil. At the time, Microsoft stated that Microsoft Security Essentials would be finalized and released before the end of 2009, in 20 markets and 10 languages. The final build was released on 29 September 2009.

Hardware requirements for Microsoft Security Essentials differ, depending on the operating system. For Windows XP, Microsoft Security Essentials requires at least a 500 MHz processor and 256 MB of RAM. On Windows Vista and Windows 7, Microsoft Security Essentials requires a 1 GHz processor and 1 GB of RAM. Under any compatible operating system, a VGA screen of 800 × 600 or higher, 140 MB of free space, and an Internet connection are also required.

On 19 July 2010 Microsoft released a technical preview of Microsoft Security Essentials 2.0. On 16 December 2010, Microsoft Security Essentials version 2.0 passed the technical preview stage and was officially released to public. This version includes Network Inspection System, a network intrusion detection system that works on Windows Vista and Windows 7 as well as a new anti-malware engine that employs heuristics in malware detection. Version 2 can also integrate with Internet Explorer to protect users against web-based threats.

Microsoft Security Essentials is a security suite designed for consumers and lacks centralized management features which are found in Microsoft Forefront Client Security. It includes the same anti-malware engine (dubbed "Microsoft Malware Protection Engine", or MSMPENG for short), and virus definitions that all other Microsoft desktop anti-malware products share, including Forefront Client Security, Windows Live OneCare, and Windows Defender.Before installation, Microsoft Security Essentials checks for the validity of the installed copy of Microsoft Windows. Microsoft Security Essentials requires no registration or personal information. Microsoft Security Essentials disables Windows Defender, since Microsoft Security Essentials also provides protection against spyware and adware

Using default settings, archived files are decompressed, and then scanned. File downloads and e-mail attachments are also scanned. Its Dynamic Signature Service attempts to better identify malicious files by checking for updates if an application exhibits suspicious behavior Before taking action against a suspect file, Microsoft Security Essentials prompts for user input. If no response is received in ten minutes, then the suspected malware is handled according to its default action, letting Microsoft Security Essentials determine what to do with the malware. System Restore points are created before removing found malware.

Microsoft Security Essentials automatically checks for and downloads virus definition updates which are published three times a day to Microsoft Update.Alternatively, users may download the updates manually from Microsoft Security Portal