I am trying to install new modules of Python on my PC running Windows 8.1 and Python 3.7 I found a solution saying "Ïnstall Microsoft Build Tools 2015". I install this package and still facing this error. Here is a screenshot(Visual c++ 14.0 error):

Please help me to sort this out, now its causing headache.

You have to install the C++ compiler that comes with Microsoft Visual Studio 15. This is because some of the underlying libraries of Python are written in C++. Both Linux and Mac OSs come with the C++ build tools built in with the operating system, Windows does not (sadly). It used to be a stand alone set of build tools one could install separately. Unfortunately, the stand alone build tools for Microsoft Visual C++ no longer exist. Instead Microsoft prefer you install their 6GB visual studio, which many old links direct to. Many of us realize that this requirement is despotic and want the stand alone installer back.

Despite Microsoft best efforts to redirect all hyperlinks(in MS blogs etc) to the new Visual Studio installer, the following location seems to host the older build tools for VS2015. However, it is going to be between 3gb and 6gb in size: https://visualstudio.microsoft.com/vs/older-downloads/

The size does not make any sense for just the C++ build tools. However, I am told this is correct. It seems in true MS fashion it ships with a lot of extra baggage most of users / developers will not even care about (I don't want to cross compile C++ for Arm etc).