In order for LanGuard to perform completely silent installations, you will need to use a silent install switch, which can usually be found on the software manufacturers website.
Microsoft Security Essentials + the updates:
mseinstall.exe /s /runwgacheck /o
Google Chrome Standalone Installer (All Users)
chromeStandaloneSetup.exe /silent /install
VideoLAN VLC (/l=1033 is the English language.)
vlc-2.0.1-win32.exe /L=1033 /S
For each piece of software you want to install, you will need to research the silent install switch and add that to the Deploy custom software deployment section.
Note: For more information on deploying custom software, please see the remediation portion of the online manual: http://manuals.gfi.com/en/lanscan2012/Default.htm#ACM/Topics/Remediating Vulnerabilities/Deploying Custom Software.htm