'node' is not recognized as an internal or external command

Node is missing from the SYSTEM PATH, try this in your command line

SET PATH=C:\Program Files\Nodejs;%PATH%

and then try running node

To set this system wide you need to set in the system settings - cf - http://banagale.com/changing-your-system-path-in-windows-vista.htm

To be very clean, create a new system variable NODEJS

NODEJS="C:\Program Files\Nodejs"

Then edit the PATH in system variables and add %NODEJS%

PATH=%NODEJS%;...

Nodejs's installation adds nodejs to the path in the environment properties incorrectly.

By default it adds the following to the path:

C:\Program Files\nodejs\

The ending \ is unnecessary. Remove the \ and everything will be beautiful again.