This started for me on Win 8/IE10 a few months back whenever I would try to access search results that brought me to social.microsoft.com or answers.microsoft.com.  Now on 8.1/IE 11, I am unable to sign in at all with my Microsoft account, even just to access email.  I've reset browser settings to default and cleared all cache many times, no change.  Works just fine in Firefox.  This is infuriating!