1. Uninstall Node using Control Panel.
2. Make sure there is nothing on your path to any node or NPM directory
3. Download Node from https://nodejs.org/
4. Run the installer
1. Select to install NPM
2. Select to add Node the path
5. You will now have a c:\Program Files (x86)\nodejs\ directory, and in it are both NPM and Node.
6. Run: npm install npm –g
1. You will now have the most up to date NPM in c:\Users\[user]\AppData\Roaming\npm\
7. Run the node installer again, and deselect NPM.
1. This will remove NPM from the c:\Program Files (x86)\nodejs\ directory
8. Now, add NPM to your path (c:\Users\[user]\AppData\Roaming\npm\)

You are now in a position to keep NPM up to date, independently of Node, and both are where they belong.