Problem: os.startfile() opens multiple instances of my external exe

I’m trying to open a stereo movie file with BGE:

I use a simple keyboard sensor to activate the following python script [text.003]:
import os

Here is the only line of content in the batch file:
StereoPlayer.exe -fss -file:doughbal-LR.wmv
(this uses the stereoplayer to open the file doughbal-LR.wmv full screen)

Here is the command line parameters for the stereoplayer:

This does work - BUT it arbitrarily opens 1 or 2 instances of the program - I only want it to open a single instance per key input. Sometimes 1, sometimes 2 instances - ARRgh!

— I initially tried to open the exe along with the movie, but could not determine the right python syntax after MANY variations. Resorted to a .bat file.
— I turned on “tap” but no change.
— I even have the properties of the stereoplayer set to allow only one instance of the player, but it still incorrectly opens multiples.
— I tried using just the exe and get similar results (however it normally opens twice on the first key event, and only once thereafter) using - os.startfile(“stereoplayer.exe”)
— I can’t determine what is causing this.

Anyone seen a similar problem? Is there anything within logic that could help suppress, or does anyone have other ideas?

Win 7, BGE 2.59.0


i 'd suggest to use

a keyboard sensor with 'all keys ’ ON – python controller

for the python script,
use the os.startfile along with keyboard detection script in documentation of the module in Blender 2.5 python api.

I’ve not found reference to the ['all keys ’ ON] python controller of which you mention - could you give me a better hint please?

I’ve looked up the “keyboard detection script” and I am trying to find/understand it also.
Is it in this area?

If you could give me an example of what you suggest I could probably work through it.

Thanks K.

@BGE_New - Kara was referring to the All Keys button on the Keyboard sensor.