When I open my Command Prompt,
the default path is C:\Users\acer>
so I want to change the path to C:\Python27
the method is as follows
i enter cd.. 2 times..
then I enter cd.. Python27 
as my Python27 folder located in C:\
however, I got this message "the system cannot find the path specified"
Can anyone help me?
Instead of 
cd.. Python27 
you need to type
cd \python27
The system cannot find the path specified in cmd