The Computer ID is calculated by generateComputerId.exe. You can run this executable manually, e.g. from the Windows Command Prompt.
The executable is located at <National Instruments>\Shared\License Manager\bin\.
If you download Volume License Manager, you can also found generateComputerId.exe in Volume License Manager folder. For example: C:\Program Files (x86)\National Instruments\Volume License Manager
Once the Command prompt is open, you can e.g. drag and drop the executable into it and press Enter
If you wish to retrieve the Computer ID from your LabVIEW application program, you can use System Exec.vi to run the executable.
Make sure you do not run the executable by itself, Windows will close the automatically-opened Command Prompt window after the executable has finished, therefore you will not be able to see the ID generated.
You can also use this executable as a step in automating NI software activation. Reference the related links below for more information.