An anti-malware suite from Microsoft for Windows XP, Vista and 7. Introduced in September 2009, Microsoft Security Essentials (MSE) replaced Microsoft's antivirus subscription service (see Windows ...
Close to a hundred issues have been addressed in November's Patch Tuesday, including six zero-day vulnerabilities in Windows.
Microsoft Security Essentials 4.0 does a decent job protecting a clean PC, but in testing its cleanup of already-infested systems wasn't thorough. You can get better protection for the same price.