Silent Install
x64
lightworks_v14.5.0_full_64bit_setup.exe /S
x86
lightworks_v14.5.0_full_32bit_setup.exe /S
Silent Uninstall
Sadly the uninstaller will open an Webpage to ask you why you like to deinstall.
x64
"%ProgramW6432%Lightworksuninstall.exe" /S
x86
"%ProgramFiles%Lightworksuninstall.exe" /S