1) download install_comtypes.py.

2) execute “install_comtypes.py” using Python.exe (3.6.1)
-right-hand click on install_comtypes.py,
-choose ‘open with’,
-choose ‘Choose default program’,
-choose ‘Browse…’,
-go to C:\Python36\ and choose ‘Python.exe’.
=> comtypes should install.