title: NPM error while installing packages on windows
body: <p>I've been trying to install dependencies for two projects and while installing <code>xml2json</code> and <code>ursa</code> packages got the similar errors:</p>
  
  <p>For <code>xml2json</code>:</p>
  
  <pre><code>C:\Users\home\Projects\project1\node_modules\node-expat&gt;if not defined npm_config_node_gyp (node "C:\Program Files\nodejs\node_modules\npm\bin\node-gyp-bin\\..\..\node_modules\node-gyp\bin\node-gyp.js" rebuild )  else (node "pangyp" rebuild )
  module.js:491
      throw err;
      ^
  
  Error: Cannot find module 'C:\Users\home\Projects\project1\node_modules\node-expat\pangyp'
      at Function.Module._resolveFilename (module.js:489:15)
      at Function.Module._load (module.js:439:25)
      at Function.Module.runMain (module.js:609:10)
      at startup (bootstrap_node.js:158:16)
  </code></pre>
  
  <p>For <code>ursa</code>:</p>
  
  <pre><code>C:\Users\home\Projects\project2\node_modules\ursa&gt;if not defined npm_config_node_gyp (node "C:\Program Files\nodejs\node_modules\npm\bin\node-gyp-bin\\..\..\node_modules\node-gyp\bin\node-gyp.js" rebuild )  else (node "pangyp" rebuild )
  module.js:491
      throw err;
      ^
  
  Error: Cannot find module 'C:\Users\home\Projects\project2\node_modules\ursa\pangyp'
      at Function.Module._resolveFilename (module.js:489:15)
      at Function.Module._load (module.js:439:25)
      at Function.Module.runMain (module.js:609:10)
      at startup (bootstrap_node.js:158:16)
      at bootstrap_node.js:598:3
  </code></pre>
  
  <p>Versions:</p>
  
  <pre><code>node v8.4.0
  npm 5.3.0
  Windows 7 Ultimate 64
  </code></pre>
  
  <p>I've run <code>npm rebuild node-expat</code> bun no effect.</p>