I attempt to run the program (IDLE) after a fresh install of Python x86 on windows 7 32-bit and it gives me this error:
"Runtime Error!

Program: C:\Program Files\Python\pythonw.exe


This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information."

Can you try to open a Command Prompt and type (with the quotes):
    "C:\Program Files\Python\python.exe" "C:\Program Files\Python\Lib\idle\idle.py" 
Do you see error messages?

I get the same error, but only when IDLE is run with the -n flag. 
In my case, the error occurs when attempting to switch back to the IDLE gui after executing a script that opens a graphics window (using the vtk module). This is with Python 2.6. 

I have Visual C++ 2010 Express installed, along with a previous install of the 2008 redistributable.

The following message is returned to the prompt:

Fatal Python error: PyEval_RestoreThread: NULL tstate

This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information.

Is this still a problem? My guess is that this issue is out of date.

I just run into this problem. I am running python 3.2, but I do have python 26 and python 27 install on the same computer.

What are the precise steps you are taking to cause this error?

What version of Windows are you using? Is it 32-bit?

Additional info on error in python 3.2
I am using 32 bit Win 7 enterprise SP1. I download and installed python-3.2.msi from python.org I than start python pythonw from window menu just like any other program. Running python command line also failed, and this is the error message:
Fatal Python error: Py_Initialize: unable to load the file system codec
LookupError: no codec search functions registered: can't find encoding

This application has requested the runtime to terminate it in an unusual way.
Please contact the application's support team for more information.

I have uninstalled python 26, 27, 32. Then reinstalled 32. Problem is still presents. I also have cygwin on my system. Python 26 and 27 worked without any issue. Python 26 that comes with cywin worked as well. I just updated my cygwin to get python 3.2 binaries from cygwin's dist. It is working.
Let me know if there is anything I can do to help.

Karen

Karen, thank you for your reply and your cooperation. This issue may 
take some time to resolve.

It looks like the error you are receiving has been addressed in 
issue11288. Can you check it out?

Yes. It is the same bug. And changing pythonhome path from c:\python26 to
c:\python32 fixes the problem. My initial google search found bug 9890, but
not 11288. Let me know if there is anything I can do.

Karen

On Mon, Aug 6, 2012 at 8:27 PM, Roger Serwy <report@bugs.python.org> wrote:

>
> Roger Serwy added the comment:
>
> Karen, thank you for your reply and your cooperation. This issue may
> take some time to resolve.
>
> It looks like the error you are receiving has been addressed in
> issue11288. Can you check it out?
>
> ----------
>
> _______________________________________
> Python tracker <report@bugs.python.org>
> <http://bugs.python.org/issue9890>
> _______________________________________
>

I'm closing this issue as a duplicate of #11288.