See
Install Python Windows I suggest downloading
2.7.2 (don't download the 3.X.X versions).
Note that if your goal is to run DRM-stripping scripts, it may be simpler to use Calibre and the 3rd party DRM-stripping plugins that can be added to it. These are written in Python, but don't require Python to be installed on your PC. See Apprentice Alf's Blog for more info.