unable to open IDLE for Python3.50rc1 on windows10 64bit AMD

[Nicky Mac]

wow - a very comprehensive answer.
However it seems I have now got it correctly reinstalled  with the correct
environment and path (as below) So I'm back to my original problem:

C:\Users\Nick>python -m idlelib
** IDLE can't import Tkinter.
Your Python may not be configured for Tk. **

On doing a repair or modify to install tcl/Tk again, the same result.

C:\Users\Nick>python -c "import sys; print(*sys.path, sep='\n')"
 gives
C:\Python\Python35\python35.zip
C:\Python\Python35\DLLs
C:\Python\Python35\lib
C:\Python\Python35
C:\Python\Python35\lib\site-packages
This looks OK,  Python35 directory contains Lib and tcl as it does on my
now working Win7 system, and Lib contains tkinter

C:\Users\Nick>path
PATH=C:\Python\Python35\Scripts\;C:\Python\Python35\;C:\ProgramData\Oracle\Java\javapath;C:\Program
Files\Broadcom\Broadcom 802.11 Network
Adapter;;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\Program
Files (x86)\ATI Technologies\ATI.ACE\Core-Static;