Microsoft Security Essentials
mseinstall.exe /s /runwgacheck
You can also run mseinstall.exe /s /runwgacheck /o
The /o tells Security Essentials to NOT perform an auto update immediately following the deployment.
The /runwgacheck option is needed or you will get error code -2147156188.
If you see error -2147156135 this means the installation file was built for a different architecture. e.g. Deploying the 32 bit installation to a 64 bit system will result in this error.
Also, error code 327424 may be returned which means that the install succeeded and a reboot is needed. This can be added to the success codes to treat it as a successful deployment.