IDLE won't run after installing Python 3.3 in Windows
Well firstly being windows I assume that you did a restart after install.
Python.org python doesn't come with the windows extensions which can be installed separately.
On windows I use winpython is totally portable and can be installed as system version includes all extensions as well as Numpy and matplotlib etc which can be a bit tricky to install otherwise.
There is enthought and anaconda packaged python a well but my choice is winpython
Give it a try and you'll definitely have a working system version.