Open using File>Open on the Shell
Well, a step toward more information... I presume by "shell" you
mean IDLE.
What is the full path to the file you are trying to open (as someone
else mentioned, Win7 "Libraries" seem to cause problems).
Why no open a Windows console (Win7 "search" for "cmd.exe", and hope
it finds it -- I've not had much luck with that search/run system, and
run it).
When you get one open, navigate to the directory containing idle.py,
and run IDLE from the console, a la:
E:\>cd Python25\lib\idlelib
E:\Python25\Lib\idlelib>python idle.py
E:\Python25\Lib\idlelib>
Then try opening your file (take note of the full path used in the
open requester).
With luck, if IDLE crashes, you will have a Python exception
traceback in the console window. Cut&Paste that traceback (all of it, up
to the command that started IDLE)* it into a response here, along with
the full path of the file you tried to open.
* Windows consoles normally don't honor <ctrl-c>/<ctrl-v> -- right
click in the console, select "mark", click-select the text (you'll have
to select the full width of the console, it uses rectangular select
area, not logical line select), then right-click again to "copy". You
can use <ctrl-v> to paste into the reply window.