Change directory (commandline window)

Ok, for some strange reason I cannot move from the "Python27" folder:
I have tried this...

Python 2.7.3 (default, Apr 10 2012, 23:31:26) 
Type "help", "copyright", "credits" or "license" for more information.

>>> from os import system
>>> system('cd')
C:\Python27
0
>>> system('cd ..')
0
>>> system('cd')
C:\Python27
0

It did not change directory; why?

[pyTony]

The system has it's own current dictionary, you want to change Python's directory by os.chdir

[Gribouillis]

os.system() is a (deprecated) function to run another program from your python program. Changing your process' working directory is different from starting another program. Use os.chdir(path) to change the current working directory and os.getcwd() to get the current working directory.