Managing personal Outlook.com account settings, security, and privacy
If you're using Windows 8, did you elect to use your Microsoft ID and password as the Start screen credentials? If so, that's probably why. When you log into Windows, you are authenticating to Windows Live/Hotmail/Outlook.com
When I purchased this new computer, I used my Bell Aliant email address to initiate service with a different password. When I shut my computer down completely and then it comes back on, my Bellaliant email address is shown on the screen and I have to type a password in to initiate Windows. I did not use anything Hotmail/Outlook related whatsoever to log into Windows, I used my Bell Aliant email address and created a brand new password just for Windows. I don't know what else could be causing it. Even when my spouse goes to log into his Outlook, he clicks on the Outlook icon or even uses Outlook.com in the URL, as soon as he hits enter from there, it automatically logs ME in instead and does not give him the option to sign in. He has to physically log me out from that screen, and only then does it display the screen where you have to enter your email address and password.
Annette Sullivan