NodeJS - NPM fails to install nodemon package - node.js

Question

I've been trying to install nodemon using npm install -g nodemon, but I keep getting the following error. Please help
C:\Users\AllJs\Desktop\FF>npm install -g nodemon
npm ERR! tar.unpack untar error C:\Users\chris\AppData\Roaming\npm-cache\nodemon\1.9.1\package.tgz
npm ERR! Windows_NT 10.0.10586
npm ERR! argv "C:\\Program Files\\nodejs\\node.exe" "C:\\Users\\AllJSAdmin\\AppData\\Roaming\\npm\\node_modules\\npm\\bin\\npm-cli.js" "install" "-g" "nodemon"
npm ERR! node v4.2.3
npm ERR! npm v2.13.1
npm ERR! path C:\Program Files\nodejs\node_modules\nodemon
npm ERR! code EPERM
npm ERR! errno -4048
npm ERR! syscall mkdir
npm ERR! Error: EPERM: operation not permitted, mkdir 'C:\Program Files\nodejs\node_modules\nodemon'
npm ERR! at Error (native)
npm ERR! { [Error: EPERM: operation not permitted, mkdir 'C:\Program Files\nodejs\node_modules\nodemon']
npm ERR! errno: -4048,
npm ERR! code: 'EPERM',
npm ERR! syscall: 'mkdir',
npm ERR! path: 'C:\\Program Files\\nodejs\\node_modules\\nodemon',
npm ERR! fstream_type: 'Directory',
npm ERR! fstream_path: 'C:\\Program Files\\nodejs\\node_modules\\nodemon',
npm ERR! fstream_class: 'DirWriter',
npm ERR! fstream_stack:
npm ERR! [ 'C:\\Users\\AllJSAdmin\\AppData\\Roaming\\npm\\node_modules\\npm\\node_modules\\fstream\\lib\\dir-writer.js:35:25',
npm ERR! 'C:\\Users\\AllJSAdmin\\AppData\\Roaming\\npm\\node_modules\\npm\\node_modules\\mkdirp\\index.js:47:53',
npm ERR! 'FSReqWrap.oncomplete (fs.js:82:15)' ] }
npm ERR!
npm ERR! Please try running this command again as root/Administrator.
npm ERR! Please include the following file with any support request:
npm ERR! C:\Users\AllJS\Desktop\FF\npm-debug.log

Answer 1

You are not allowed to write to C:\Program Files\nodejs\node_modules\. Check your npm configuration, it should not be trying to store packages there.
Run npm config get prefix to determine the current npm folders prefix. On my Windows machine this will return something in the form:
C:\Users\<My Username>\AppData\Roaming\npm
which is a user writable location.