Problem: Microsoft visual C++ 10.0 required, although VS 2017 is installed

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VisualC++

Python3.6

I want to install a package on my Windows 10 with python3.4 using

pip install pyinsane2

. It downloads the .zip folder successfully but then shows me the error message: Microsoft Visual C++ 10.0 is required. Get it with Microsoft Windows SDK 7.1: "linktodownload"
But I have VS 2017 already installed on my computer and its working fine. Anyway, I clicked the link, downloaded Microsoft Windows 7.1 from there and started the setup. In the setup it tells me: 'Some Windows SDK components required the RTM .NET Framework 4. Setup detected a pre-released version of the .NET Framework 4. If you continue with the setup these components will not be installed. If you want to install these components, install the .NET Framework 4 from "link" and retunr to setup. So, again, i went on the link and donwloaded the .NET Framework 4.7.1 from microsoft, only to be told in this setup, that this Frameowork is already installed on my computer.
So it is not a file missing or asking for it, it just tells me the entire visual C++ is missing.

What I have tried:

I tried uninstalling and re-downlaoding both downlaods and it didnt help. I read somewhere it has something to do with the envr var VS100COMNTOOLS and you have to

set

it up in the command window, but that didn't help either. Mine is saying

VS100COMNTOOLS = C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC

So is this set up correctly and what can I do so the system recognizes Visual c++