Delay Analyzer can be silently installed from the command line or a Powershell script in the standard way:
msiexec /i steelray-delay-analyzer-x.xx.x-setup.msi /quiet /qn
By default, the installation folder will be C:\\Program Files (x86)\\Steelray Software\\Steelray Delay Analyzer
To automatically install a license key: after the application is installed, but before the application is run for the first time, write the license key to a file named license and copy it to the installation folder.
When Delay Analyzer is launched and detects an expired license, it will connect to steeray.com to check if the key has been renewed, and if so, it will automatically install the new key.  If it is unable to connect to steelray.com for network or security reasons, it will look in its installation folder, and if it finds a license file,  attempt to install the key contained in that file.