title: virtualenv on Windows10 gives error:The path python3 does not exist
body: <p>I'm trying the tutorial <a href="https://cloud.google.com/python/getting-started/using-cloud-datastore" rel="noreferrer">Using Cloud Datastore with Python</a>, but when I run:</p>
  
  <pre><code>virtualenv -p python3 env
  </code></pre>
  
  <p>I got an error:</p>
  
  <pre><code>The path python3 (from --python=python3) does not exist
  </code></pre>
  
  <p>I checked the python version by running:</p>
  
  <pre><code>python -V
  </code></pre>
  
  <p>It gives me:</p>
  
  <pre><code>Python 3.5.2 :: Anaconda 4.1.1 (64-bit)
  </code></pre>
  
  <p>I run <code>set python</code> to see the Environment variables, which gives me:</p>
  
  <pre><code>Environment variable python not defined
  </code></pre>
  
  <p>An annoying thing is that, this is a lab machine which I don't have the admin right, I need to email the IT Admin to change the Environment variables.</p>
  
  <p>Tried:<code>virtualenv -p python env</code></p>
  
  <p>It gives me:</p>
  
  <pre><code>The path python (from --python=python) does not exist
  </code></pre>
  
  <p>Seems there is no way around until the environment variable is fixed.</p>