Download ionic design 0.4.0 (from the link https://dashboard.ionicframework.com/personal/downloads)
Install, and run.
It informs you that it will install 0.4.2 upon exit.
It removes 0.4.0 and does not install 0.4.2
But hey, I finally got it to not fail from the “ionic is not a command” path problem.
Ya, I know, only six people use Ionic in Windows…