Cannot sign in to windows live mail (2012). All passwords are rejected.

Have been using windows live mail 2012 successfully for a couple of years.  Yesterday, a pop-up box appeared for the first time asking me to sign in.   (Has sign-in happened automatically before?)  When I attempted to sign in, I received an error message:  "the email address or password is incorrect.  Please try again."  I rechecked and both were correct, but I carefully retyped them and tried again.  I even tried using my Comcast password to no avail.  So, I logged into my Microsoft account and changed the password.  When I tried signing into windows live mail with the new password, I still continued to get the same error message.  But since email still worked, I gave up and turned off the "sign in" prompt.  Today, however, I noticed that I cannot access my email contacts list without being signed in to windows live mail.   So, I'm back to square one:  unsuccessfully trying to sign in.  After both an online chat and a telephone conversation with Microsoft support, here I am.   Can someone help?