python virtualenv packages path not found

I practice to install django with virtualenv in windows.

When i type "django-admin.py startproject mysite", 

it can not import django.core and the error message is    

" from django.core import management

ImportError: No module named django.core"

find the solution from below link

http://stackoverflow.com/questions/8012956/python-django-virtualenv-windows

This is because, it still use the python.exe in default (C:\python27) not the python.exe in my virtualenv (D:\venv\Scripts).

using the ftype to check the Python.file

D:> ftype Python.file

using the ftype to change the Python.file

D:\ftype Python.file = "D:\venv\Scripts\python.exe" "1%" %*