Python scripts stopped running on double-click in Windows

Steps to cure this problem

1) Right click on your script.
2) Choose properties and then
3) Change the option how to open your script (set it as python).

This will make all of your .py extension scripts into running on double click in windows

Double-clicking is not related to PATH, but extension association.

Check register extension option when you install(or recover) the python.

Removed all python versions and folders. Installed WinPython-64bit-2.7.5.1 package (as before) and everything works now. I can run my scripts by double-clicking them. Really strange.