The epydoc documentation says:
The graphical interface can be invoked with the epydocgui command, or with epydoc.pyw in the Scripts subdirectory of the Python installation directory under Windows.
I've tried running the epydoc.pyw file directly, and calling it from command line i.e. >>> python epydoc.pyw and >>> epydoc.pyw, both from the scripts directory in my python directory.
How am I supposed to run epydoc.pyw?
In order to use the gui of epydoc, click double on the file epydoc.pyw which is often located at C:\Python27\Scripts
Regarding your question in the comments: 1) open a normal console, 2) navigate to your Script folder and 3) then call the following e.g. to generate uml diagramm. See commandline documentation