Matplotlib unable to plot on my windows 8.1 machine.

I have installed the latest version of matplotlib but it's unable to plot.
Below is the error message, please help:

Traceback (most recent call last):
  File "C:/Users/Physics
department/Desktop/Python_programs/2d_densityplot.py", line 2, in <module>
    import matplotlib.pyplot as plt
  File "C:\Python36\lib\site-packages\matplotlib\__init__.py", line 200, in
<module>
    _check_versions()
  File "C:\Python36\lib\site-packages\matplotlib\__init__.py", line 194, in
_check_versions
    module = importlib.import_module(modname)
  File "C:\Python36\lib\importlib\__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
ImportError: DLL load failed: The specified module could not be found.

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