Environment Variables

[Krishna]

Environment variable set up is the most confusing part for me all the
time. Please help me with the following questions:

When I install python in a new system, I will go to environment
variables (system variables) and set "path" pointing to C:\Python25
and thats all I do.
I type python from "cmd" window and its converting to python window
for python execution. All fine up to this point.
Now, I want to drag and drop python (.py) files to this window and
execute it. My python files are located in different directories
inside C: and outside C:. When I do that, I get errors and the file is
not found and its not imported. ALso, inside the .py file, if I have a
command to open a different file, it doesnt see that either. How do I
overcome these basic difficulties in python. I wish I can open any
file and work on that using python.


Thanks for your help!
Krishna