<p>Just add:</p>
<pre><code class="lang-auto">;C:\Program Files\nodejs\
</code></pre>
<p>To the end of your <strong>Path</strong> variable on the <strong>“User variable”</strong> section of the Variables d’environnement on the Propriétés système.</p>
<p>After that, reopen your invite de commandes and type</p>
<pre><code class="lang-auto">npm
</code></pre>
<p>This should work.</p>