I've installed meteor through the official installer as the image shows:
But the command is still not working on my terminal even when I restart the machine! The .meteor folder on my /users/$USER$ folder is non-existent. How can I install meteor under Windows 10?
I had the same problem, this is what I did.
I already had git installed on my computer for other reasons, but make sure you have git and 7z installed. Additionally, and I don't know if it's because my migration to Windows 10 wasn't horribly successful, but make sure that 7z is in the path. No need to reboot, just close the command window and reopen. Type 'path' command and it should have the 7z at the end where you added it.
Once you're ready, get where you want to install meteor. I just used my home directory, then type 'git clone http://github.com/meteor/meteor.git'
That will download the latest meteor from GitHub into a directory named meteor, once it's finished then you'll want to add that directory to your path as well. Again, close the command prompt window and reopen and use the path command to verify the path is there, and then start working on your new meteor projects.