Problem with cx_freeze app only on one pc

[floatingshed]

I have made a python app and used cx_freeze to distrubute it to my colleagues as a windows exe.
It is currently working on 16 machines using windows 7,8 and 10
Today I tried to install it on a windows 10 machine and got this error:

\lib\ctypes\__init__.py*\, line 348 in __init__ self._handle=_dlopen(self._name, mode)
OSError: [WinError 126] The specified module could not be found.

I've just dug out an old laptop and installed the app, no problem. It is definitely a problem with that one machine, but how? why?

Does anyone have any experience of similar issues?
Thanks.