On Fred's laptop, I attempted to run this installer:

Setup-bundled-0.0.2-20160331-23.exe

After logging into the first page of the installer, the second page is greyed out and there's a javascript error:

Uncaught (in promise) Error: Command failed:
C:\WINDOWS\system32\cmd.exe /s /c "where VirtualBox"

And the installer is blocked / cannot proceed.

Screenshot (scroll right for the JS console details):

http://snag.gy/u48jU.jpg