Code I scraped together that will:
1 dertermin OS
2 Update MSE
3 Full Scan with MSE
File: MSE-Update-Scan-Vista-8.bat
rem - MSE: Update and scan system from CMD as a background process.
@ECHO OFF
CLS
ver|find "Windows XP" > NUL
if errorlevel 1 goto 2K
ECHO Windows XP Detected.
goto END
:2K
ver|find "Windows 2000" >NUL
if errorlevel 1 goto 2k3
ECHO Windows 2000 Detected.
goto END
:2K3
ver|find "Version 5.2" >NUL
if errorlevel 1 goto WinVista
ECHO Windows 2003 Detected.
:WinVista
ver|find "Version 6.0" >NUL
if errorlevel 1 goto Win7
ECHO Windows Vista Detected.
Echo Updating Microsoft Security Essentials Signatures
"%programfiles%\Microsoft Security Client\mpcmdrun.exe" -SignatureUpdate
Echo Run Full Scan:
"%programfiles%\Microsoft Security Client\mpcmdrun.exe" -scan -scantype 2
:Win7
ver|find "Version 6.1" >NUL
if errorlevel 1 goto Win8
ECHO Windows 7 Detected.
Echo Updating Microsoft Security Essentials Signatures
"%programfiles%\Microsoft Security Client\mpcmdrun.exe" -SignatureUpdate
Echo Run Full Scan:
"%programfiles%\Microsoft Security Client\mpcmdrun.exe" -scan -scantype 2
:Win8
ver|find "Version 6.2" >NUL
if errorlevel 1 goto ERR
ECHO Windows 8 Detected.
Echo Updating Microsoft Security Essentials Signatures
"%programfiles%\Windows Defender\MpCmdRun.exe" -SignatureUpdate
Echo Run Full Scan:
"%programfiles%\Windows Defender\MpCmdRun.exe" -Scan -ScanType 2
goto END
:END
ECHO.