python and command shell on Windows

[josu]

Hi

I am trying to execute a windows command based on a shell by mean of
python. I have proven subprocess

test=subprocess.Popen
(['shell_command'],shell=True,stdin=PIPE,stdout=PIPE)

Initally, all seems ok, but, after seconds the python shell is frozen.

Does someone know alternative ways valid for windows OS?

Thanks in advance

josu