Blew it on my Node.js module location-- how to reset?

I'm using WebStorm 5.0.4.  In my project I clicked on the Node icon in the toolbar and selected the wrong directory for my core modules (wrong lib folder.)

Now, when I go into the Node.js settings I'm told that Node.js v<<latest version>> is set up.  I'm not sure what the 'edit usage scope' link does to the right of that, but is there a way to reset my Node settings and start again?