Microsoft’s free Security Essentials antivirus software identified 98% of over half a million malware samples. Independent testing company AV-Test.org gives it a “very good detection score” of 98.4%. Symantec blasted the free software as a “poor” product with “average detection rates” Microsoft’s software can be downloaded for Windows XP Service Pack 3 (SP3), Vista SP2 and the final code of Windows 7 from the operating system’s operating system before installing it.”]
Source: https://www.csoonline.com/article/2124456/independent-tester–security-essentials–very-good-.html