1. Grab the latest version of the full installer from Google's website:
Google Earth is a downloadable software solution that comprises satellite imagery and maps with most locations around the world, giving you the power to browse all of them straight from your desktop. Download Latest version of Google Earth for Windows 10 (64/32 bit). Google Earth is a virtual globe map and geographical information program that was originally called EarthViewer 3D created by Keyhole Inc a Central Intelligence Agency CIA funded company acquired by Google in 2004 see In Q Tel It maps the Earth by the superimposition of images obtained from satellite imagery aerial photography and geographic information system GIS onto a 3D globe.
https://support.google.com/earth/answer/176155?hl=en&ref_topic=2376762
(as of 2015/06/09, the direct link to the Windows installer is here: http://dl.google.com/dl/earth/client/advanced/current/googleearthprowin.exe)
2. The command line to install is simple: 'googearthprowin.exe OMAHA=1' (without the quotes)
Thanks to aidtopia, who provides this info in this thread: https://productforums.google.com/forum/#!msg/maps/gnP4HYZhUdQ/AiHHf1Cx_vcJ
3. From there, the registry lines hayds provided should work:
reg add 'HKLMSOFTWAREWow6432NodeGoogleGoogle Earth Pro' /v 'Username' /d '[email protected]' /f
reg add 'HKLMSOFTWAREWow6432NodeGoogleGoogle Earth Pro' /v 'Passport' /d 'GEPFREE' /f
reg add 'HKLMSOFTWAREWow6432NodeGoogleGoogle Earth Pro' /v 'Passport' /d 'GEPFREE' /f
Setup Type: Windows Installer (Delivered as an EXE)
Deployment Method Used: Windows Installer Command Line (No MST)
Platform(s): Windows