pip is unfortunately a a bit hit and miss on Windows. The (IMO) 'correct' way to install package on windows is to first install Anaconda Python (https://www.continuum.io/downloads) and then:

0) Check if the package came preinstalled with Anaconda

1) if not try to use conda to install packages,

2) if conda doesn't have the package, see if it's been uploaded here: http://www.lfd.uci.edu/~gohlke/pythonlibs/

3) try pip.