Could not find a version that satisfies the requirement tensorflow
I solved the same problem with python 3.7 by installing one by one all the packages required 
Here are the steps:

Install the package
See the error message:

couldn't find a version that satisfies the requirement -- the name of the module required

Install the module required.
Very often, installation of the required module requires the installation of another module, and another module - a couple of the others and so on. 

This way I installed more than 30 packages and it helped. Now I have tensorflow of the latest version in Python 3.7 and didn't have to downgrade the kernel.
I installed the latest version of Python (3.6.4 64-bit) and the latest version of PyCharm (2017.3.3 64-bit). Then I installed some modules in PyCharm (Numpy, Pandas, etc), but when I tried installing Tensorflow it didn't install, and I got the error message: 

Could not find a version that satisfies the requirement TensorFlow (from versions: )
      No matching distribution found for TensorFlow.

Then I tried installing TensorFlow from the command prompt and I got the same error message.
I did however successfully install tflearn. 
I also installed Python 2.7, but I got the same error message again. I googled the error and tried some of the things which were suggested to other people, but nothing worked (this included installing Flask). 
How can I install Tensorflow? Thanks.