Compared to *NIX computers, which come with Python installed by default, Windows OS does not include Python out of the box. However, MSI installer packages are available to install Python on a number of Windows-based environments. These installers are designed to be used by a single user, rather than all users of a particular computer. However, it is possible to configure them during installation to allow all system users of a single machine to access Python.
As Python contains platform-specific code for a variety of operating systems, to minimize the amount of unneeded code, Python only supports Windows OSes as long as they are supported by Microsoft; this includes extended support, so anything that has reached end of life is not supported.
As such, Windows XP and older cannot install any Python version beyond 3.4. The Python documentation still states that Windows Vista and newer can install 3.6 and later versions, but Windows Vista reached end of...