Graphics py not found

[snippsat]

...even 'c:\>python' throws a 'unexpected character after line continuation character' error

You are mixing up the use Python interactive shell and cmd
Introduction to the Windows Command Prompt(cmd)

To make your error and fix it:
I start cmd:

Microsoft Windows [Version 10.0.14393]
(c) 2016 Microsoft Corporation. Med enerett.

C:\WINDOWS\system32>cd\
C:\>python
Python 3.6.0 (v3.6.0:41df79263a11, Dec 23 2016, 07:18:10) [MSC v.1900 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> c:\>python
  File "<stdin>", line 1
    c:\>python
             ^
SyntaxError: unexpected character after line continuation character
>>> exit()

# Now i am on command line and not python shell
C:\>python -V
Python 3.6.0

C:\>pip -V
pip 9.0.1 from c:\python36\lib\site-packages (python 3.6)

# Start shell again
C:\>python
Python 3.6.0 (v3.6.0:41df79263a11, Dec 23 2016, 07:18:10) [MSC v.1900 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> print('hello world')
hello world
>>>