Go to this page and download the Windows version of Enthought Python Distribution (EPD):
Double-click the .msi file to start the automatic installer. Go through the installer with all the default options selected.
After installing, you can check that everything is up and running by opening Start > Enthought > PyLab.
Spyder
Spyder lets you edit and run Python scripts.
Go to this page to download the Windows version of Spyder:
You can select the link named something like "spyder-2.1.13.win32.exe". After downloading, select the same Python folder that you chose for Enthought. If you did not change anything, you can go with the default values and click next all the way.
After installing, open up the Start menu and search for spyder. A file named "spyder.bat" will show up.
Click "spyder.bat" and Spyder launches.