Norton Anti-Virus 2014 (21.3.0.12) Version And Microsoft Security Essentials Software

Microsoft Security Essentials

Antimalware Client Version: 4.5.216.0
Engine Version: 1.1.10701.0
Antivirus definition: 1.177.544.0
Antispyware definition: 1.177.544.0
Network Inspection System Engine Version: 2.1.10502.0
Network Inspection System Definition Version: 111.25.0.0

 

I had done a full scan of Windows Vista service Pack 2 and  Microsoft Security Essentials and sofware didn't detect vulnerabilites and then i installing Norton Anti-virus 2014 (21.3.0.12) and done a full scan and find Trojan.Fakeavlock, then Microsoft Security Essentials crashed Norton Anti-virus 2014 (21.3.0.12) and saying Microsoft Security Essentials had cleaned Trojan.Fakeavlock. then restarted computer and then Norton Anti-virus auto-protection detected  Trojan.Fakeavlock and Quanatine it.

 

My questions is why Microsoft Security Essentials didn't detect this in the first place? Are Hackers controling the software of Microsoft Security Essentials?