*WARNING!* Making changes to the Windows registry incorrectly can cause serious problems that may require you to reinstall Windows.
Getting the Create a World tool to work with the Steam version of the game requires edits to the Windows registry. I'm going to preface this guide by saying that by far the simplest way to get the Create a World Tool working is to register your game on The Sims 3 website then download and install the game through Origin.
