By default, Outlook 2007 displays buttons on the left side of the screen that allow you to quickly access the different elements of the program, including the calendar. However, every aspect of this view is customizable and you may have accidentally disabled this button. You can bring the calendar button back to the left side of the window in Outlook 2007 to allow single-click access to the calendar, or use the Outlook to-do pane to see your mail and upcoming Outlook calendar items simultaneously.
Restore the Outlook Calendar Button
Launch Outlook 2007. Click the "View" menu at the top of the screen, then click "Navigation Pane" followed by "Normal." This displays the navigation pane on the left side of the window. If you already have the navigation pane displayed, skip this step.
Right-click one of the buttons on the navigation pane (such as "Mail") and click "Navigation Pane Options."
Place a check in the box labeled "Calendar" and click "OK." The calendar button will appear on the navigation pane.
Display Upcoming Calendar Items
Click the "View" menu at the top of the screen, then click "To-Do Bar" followed by "Normal." The To-Do bar will open on the right side of the window.
Click "View" and "To-Do Bar" again, and verify that the word "Appointments" has a check next to it. Click "Appointments" if there is no check to display upcoming Outlook calendar events.
Click the "Arranged By" drop-down menu to re-sort your calendar items by different criteria including the start date and due date. You will now be able to view your selected calendar items in the Outlook to-do pane.