If you install Node using the windows installer, there is nothing you have to do. It adds path to node and npm.
You can also use Windows setx command for changing system environment variables. No reboot is required. Just logout/login. Or just open a new cmd window, if you want to see the changing there.
setx PATH "%PATH%;C:\Program Files\nodejs"
Add a system variable named "node", with value of your node path. It solves my problem, hope it helps.
Great answers, but you could just open the command prompt and type in
SET PATH=C:\Program Files\Nodejs;%PATH%
If you already have node installed, your path variable is set up and you suddenly start getting this error; try updating to the latest version.
This worked for me going from 6.9.2 to 6.10.
As you're using Windows, installation should automatically edit the %PATH% variable. Therefore, I suspect you simply need to reboot your system after installing.
In Windows, you need to set node.js folder path into system variables or user variables.
1) open Control Panel -> System and Security -> System -> Advanced System Settings -> Environment Variables
2) in "User variables" or "System variables" find variable PATH and add node.js folder path as value. Usually it is C:\Program Files\nodejs;. If variable doesn't exists, create it.
3) Restart your IDE or computer.
It is useful add also "npm" and "Git" paths as variable, separated by semicolon.
Worked for me by running the command prompt as an administrator
Be aware that the Path is case sensitive. I tried setx PATH and it didn't work. In my case it was setx Path. Make sure your CMD run as Administrator.
setx Path "%PATH%;C:\Program Files\nodejs"
Now just restart your command prompt (or restart the PC) and the node command should be available.
Source: Stackoverflow.com