'vue' is not recognized as an internal or external command,
I had the same issue.
Here the quick fix.
after running the following command (as Admin)
npm install --global vue-cli
It will place the vue.cmd in the following directory
C:\Users\YourUserName\AppData\Roaming\npm
at least for me it's there.
To use vue as command in cmd. Open the cmd as admin and run the the following command.
setx /M path "%path%;%appdata%\npm"
Now restart the cmd and run the vue again. It should work just fine.