I noticed today that my Outlook 2007 calendar is missing ALL appointments
prior to the last week of July 2008. Also, I got a reminder notice for 4
appointments but I can't do anything with the reminders because it can't see
the appointment.

I haven't done anything to my computer other than accept a McAfee security
update this morning that required I restart the computer. It was after this
that I noticed the calendar items were gone.