Have you tried logging in direct to Outlook.com, in your browser? The name changed from Hotmail quite a while ago (About 2years, I think) But for you, it is only a name change.
How did you originally access your account?
As far as I am aware, the preview you see is merely a new app introduced by MS for Office365. You are not obliged to use it. But a user may be able to confirm that.