This problem started a few days ago when my Hotmail screen kept changing to Outlook.  I kept clicking the Option button to change it back to Hotmail.  Now, it has changed permanently to Outlook from Hotmail.  However, when I log onto my account, the Outlook screen becomes blank after about 5 seconds.  What is perplexing is that this happens only on this computer, and NOT when I log onto Outlook on my laptop.  Also, when my son logged onto his Outlook account on this computer, it works okay.   In other words, this is happening ONLY with my Outlook account.