How to install Tensorflow on Python 2.7 on Windows?

Elaborating a bit on dirty_feri's answer as it's not quite up to date.

Tensorflow for Windows is only supported with Python 3.5 and Python 3.6 (since 1.2). As you are downloading via pip you will be receiving the latest 1.2 version so you should be able to run on 3.6.

There should be no need to use the Anaconda version of Tensorflow, the distribution is not supported and, if you are running anaconda, the pip version does just fine.

If you still require python 2.7 support for other projects then may I suggest the use of an environment manager like anaconda or virtualenv to allow you to have multiple versions of python running nicely at once.

Once you have a supported version of python installed you should be able to run pip install tensorflow and it should install in a few minutes.

Full installation instructions are available here: https://www.tensorflow.org/install/install_windows

If you only need TensorFlow because of Keras and your are on Python 2.7.x, you can avoid installing Tensorflow(Google) and replace it by CNTK(Microsoft). According to Jeong-Yoon Lee CNTK is a lot (about 2 to 4 times) faster than TensorFlow for LSTM (Bidirectional LSTM on IMDb Data and Text Generation via LSTM), while speeds for other type of neural networks are close to each other. Your Keras code does not need to be modified (I checked it with 2 examples of Keras using TensorFlow and succesfully replaced TensorFlow with CNTK, without changing anything the Keras code.

So how do you install it?

-CPU-only version of CNTK:

pip install https://cntk.ai/PythonWheel/CPU-Only/cntk-2.4-cp27-cp27m-win_amd64.whl

-GPU version of CNTK:

pip install https://cntk.ai/PythonWheel/GPU/cntk-2.4-cp27-cp27m-win_amd64.whl

-Test CNTK install:

python -c "import cntk; print(cntk.version)"

-Install Keras: The Python Deep Learning library

pip install keras

-Enable CNTK as Keras back end iso TensorFlow

modify the "keras.json" file under %USERPROFILE%/.keras

{
    "epsilon": 1e-07, 
    "image_data_format": "channels_last", 
    "backend": "cntk", 
    "floatx": "float32" 
}