Regardless of testing and results, Windows 7 vulnerable to attack and is unsupported by Microsoft.
i) Users should upgrade away from previous versions of Windows (ie. 7, 8 and unsupported 10 builds). As of this post, Windows 10 v1903 is the latest stable version from Microsoft.
ii) Microsoft Security Essentials does not provide adequate protection compared to Windows Defender Antivirus for Windows 10. For instance, W10 OS has integrated SmartScreen, Exploit protections and more!
Takeaway; Windows 10's built-in Antivirus protection is an all round better solution than older versions of Windows and their Antivirus companions.
I reckon MSE will be phased out soon. Does it still receive program updates (not signature updates)?