If I save my code files as .pyw, no console window appears - which is what I want - but if the code includes a call to os.system, I still get a pes
.pyw
os.system
You could try using the subprocess module (subprocess.Popen, subprocess.call or whatever) with the argument shell=True if you want to avoid starting a console window.
subprocess.Popen
subprocess.call
shell=True