python 3.5.0rc1 problem opening IDLE in windows

[Nicky Mac]

Dear python team
since windows applied some updates last night to my windows 10 and windows
7 systems,
I can't open anything with IDLE as I usually do.
On windows 10 (64bit with 64bit python), I performed the installation
repair procedure.
* Edit with IDLE does not appear as an installed windows program.
* when I open my usual shortcut to IDLE (
C:\Python\Python35\Lib\idlelib\idle.py)
 something briefly flashes on the screen *and immediately disappears.*
* if I directly open a python program in windows, I get these options (as
usual):-
    edit with IDLE     (-> python launcher for windows console)
    edit with IDLE      (-> edit with IDLE (64bit))  - which I always
use, *nothing
happens*

Any ideas gratefully received!!!
sincerely
Nick "Mac" McElwaine