Microsoft Security Essentials (codenamed Morro) is a free antivirus software created by Microsoft that provides protection against viruses, spyware, rootkits, and trojans for Windows XP, Vista, and 7. Microsoft has always recommended that its users use real-time antimalware protection, but the release by the end of this year will mark the company's first free solution.

MSE replaces Windows Live OneCare -- a subscription antivirus service -- and Windows Defender, which only protects users from adware and spyware. MSE is a small-footprint program ideal for computers that lack processing power or broadband Internet connections, such as netbooks.

MSE is available as standalone 32-bit and 64-bit downloads for Windows XP, Windows Vista, and Windows 7. It's very easy to install Security Essentials using it is even easier than one might expect.

Updates and upgrades are automatic, so there's no need to worry about having the latest protection. It's easy to tell if you're protected - when the Security Essentials icon is green, your status is good. It's as simple as that.

Microsoft announced Morro on November 18, 2008. It marked a change in Microsoft's consumer antivirus marketing strategy. Instead of offering a subscription antivirus with a host of other tools -- parental controls, photo backup, and a firewall, Morro would be free for all genuine installations of Windows and simply offer protection against malware. Microsoft Forefront will be offered alongside Morro, with central management tools not present in Morro.