I'm on Windows 7

I've used Live mail 2011 calendar for over a year without ever signing in the calendar has all my important events/birthdays etc.

Since creating an account and signing in these have now all vanished and I have a blank calendar.

How can I restore my calendar to its previous state?

(I have run regular monthly backups to an external drive - will the original be stored on it ? if so where and how do I restore it)

thanks

Desperate Bob
I am trying to make the calendar on my PC (using Microsoft Office Outlook) available on my outlook.com account, but all I end up with is two calendars in Microsoft Office, one from my Hotmail, the other my PC original. On outlook,.com I only have the one blank calendar. I cannot erase the blank one in Outlook or outlook.com. I have tried deleting everything and starting from scratch to no avail. I even deleted the profile, reinstalled the Hotmail Connector, etc.  So frustrated! Ten hours and I can't find a thing online or in Help. All I want to do is sync my calendars so I can see it on my Surface and phone and my PC and change it any of them. In this day and age, this should not be so difficult.