UPDATE: In January 2017 I disabled Edge on a new Windows 10 install by simply renaming the "C:\Windows\SystemApps\Microsoft.MicrosoftEdge_8wekyb3d8bbwe" folder. (If you are asked to allow administrator privileges be sure to answer in the affirmative.) Renaming this folder was not possible in the past without following the more detailed steps below. This much simpler approach achieves the exact same results as the more complex instructions below! However, for older installations and/or Windows upgrades the below instructions may still be the only answer.