"...wiped out an entire month's worth of entries in calendar, and my address book"

I got the following from my friend:

XP Home and Office 2000

"Outlook did a backup.

When it did it, it wiped out an entire month's worth of entries in calendar,
and my address book.

Upon restarting Outlook: I got:

"The location messages are delivered to has changed for this user profile.
To complete this operation, you may need to copy the contents of the old
Outlook folders to the new Outlook folders. For information about how to
complete the change of your mail delivery location, see Microsoft Outlook
help."

"Some of the shortcuts on the Outlook bar may no longer work. Do you want
Outlook to re-create your shortcuts? All documents you have created will be
removed. Yes Or No?"

I clicked no, and all calendar and contacts that I have added since the last
backup disappeared.

They appear to be irretrievable because I tried to open the backup file and
that was the same. "


I need two kinds of help.
1. To recover the data
2. To never have this happen again