ImportError: No module named virtualenv

I am using Django 1.3.7 and python 2.7.6 on windows7 I got an error when I executing my manage.py in this line of code

import shutil, sys, virtualenv, subprocess

amd running it, I got this error

C:\Django-Proj\>python manage.py update_ve
Traceback (most recent call last):
  File "manage.py", line 4, in <module>
    import shutil, sys, virtualenv, subprocess
ImportError: No module named virtualenv

Does anyone have an Idea about my case?

Install virtualenv using pip install virtualenv. If you have it already installed, try reinstalling it by removing it with pip uninstall virtualenv and then reinstalling it. Good Luck.

I had to install virtualenv with the -H flag to set HOME variable to target user's home dir.

sudo -H pip install virtualenv