Calendar not displaying when clicking on Calendar button in Outlook 2003

For some reason, when I click on the Calendar button in Outlook 2003,
the calendar no longer shows up. I just get an empty left pane with
only the option of "Open a Shared Calendar" option available. The Menu
bar at top doesn't even change to reflect that I am in the Calendar.

However, when I right-click on the Calendar button and choose to open
in New Window, the new window does open up with the Calendar displaying
correctly. Furthermore, when I use the Folder List, the Calendar
displays correctly.

I have tried resetting all the options to Default under the Help menu
but to no avail. Please help.