py launcher defaults to the free threaded executable on Windows

[JordanSchlick]

Bug report

Bug description:

Using py.exe on Windows, such as when directly executing a .py file, results in the free threaded version of Python being launched.
Even setting py.ini to launch the regular version does not fix this behavior. This results in a situation where a py file can not find modules installed by pip in the same terminal as they are run under different versions of Python.

In my case it always launches python3.14t.exe:

C:\Users\Admin>py --list
 -V:3.14t         Python 3.14 (64-bit, freethreaded)
 -V:3.14 *        Python 3.14 (64-bit)
 -V:3.11          Python 3.11 (64-bit)
 -V:3.9           Python 3.9 (64-bit)
C:\Users\Admin>py -3
Python 3.14.3 free-threading build (tags/v3.14.3:323c59a, Feb  3 2026, 16:00:26) [MSC v.1944 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>>

CPython versions tested on:

3.14

Operating systems tested on:

Windows

[JordanSchlick]

If anyone finds this and needs a jank workaround for this you can rename HKEY_LOCAL_MACHINE\SOFTWARE\Python\PythonCore\3.14t to HKEY_LOCAL_MACHINE\SOFTWARE\Python\PythonCore\0.14t
This makes it sort as the oldest version so py.exe will no longer pick it. You may need to use the user registry hive if you have a user installation instead of a system wide installation.