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

[Nicky Mac]

I have run the install (and repair) which explicitly includes Tcl/Tk and l
have this problem:

Microsoft Windows [Version 10.0.10586] (c) 2015 Microsoft Corporation. All
rights reserved.

>    C:\Python\Python35\python.exe -m idlelib
** IDLE can't import Tkinter.
Your Python may not be configured for Tk. **

Please suggest how this can be fixed
any support greatly appreciated

Nick  McElwaine