Download and install Python: (check on Add Python on the path)
https://www.python.org/ftp/python/3.6.2/python-3.6.2-amd64.exe
Run this from a terminal Window (cmd):
pip3 install --upgrade tensorflow
To test it:
c:\>python
Python 3.5.2 (v3.5.2:4def2a2901a5, Jun 25 2016, 22:18:55) [MSC v.1900 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import tensorflow as tf
>>> hello = tf.constant( "Hello world" )
>>> session = tf.Session()
>>> print( session.run( hello ) )
b'Hello world'