Question about Outlook Express

I have a Macbook Pro OS X 10.7.4 on which I run Parallels Desktop 7 to create a virtual machine on which I have installed Windows 7 and several Windows programs.  Typically, I run the virtual Windows system exclusively, but during day-long work sessions will toggle to meshed "hand shaking" mode that enables me to use the browser, email, and other program running on the Mac.  Yesterday this worked fine until mid-afternoon when I noticed that email wasn't updating, and Internet access became slow and then stopped altogether.  Attempts to resolve the issue quickly didn't work, so I let it be until I finished my day's work at about 6 p.m.  After closing the Windows virtual machine I began problem solving steps on the Mac; network settings were okay, no other problem was readily apparent except the lack of Outlook 2011 for Mac and Firefox browser access to the Internet.  Everything I tried failed to resolve the issue.  Outlook was running, showing read and unread messages in the inbox, and numerous saved files in a large number of archive folders and subfolders, connections to three IMAP accounts, and an open .PST archive of older email messages transferred from my old Windows desktop running XP and Office Outlook 2007.  Finally, I decided to reboot to see if this would unstick the system.  When the new boot was completed Firefox accessed the Internet just fine.  Outlook, however, had been completely transformed: ALL of my former settings, accounts, undeleted current files and archived saved files, contacts and calendar items had disappeared; in the ~\documents\microsoftuserdata\office 2011 identities folder there is just a single Main Identity file that contains none of my personal information; but I had several identities and backup, saved identity files in that identities folder previously!  I have an Apple router/backup drive that automatically takes snapshots of changed files and daily does a more complete backup.  Checking these with the intention of restoring an earlier Outlook identities folder to recover everything, to my dismay I found that only the "ground zero" unmodified Main Identity file exists in all the previous instances of the folder that I checked, even though these were saved while Outlook was working as expected and contained all my settings, etc.  I found Microsoft's instructions to copy the identity, then rebuild the identity database, which I did, but unfortunately this only re-established the first installation version of the Main Identity...not my well-seasoned Main Identity built up over several years.  Must I simply kiss it all goodbye and start all over again, or is there some technically sophisticated way I can locate and restore the missing Main Identity somewhere in my Time Machine backups?  I am curious how such a catastrophic failure could occur, one that wiped clean even the Identities I wasn't using at the time, and everything included in every one of the .olm files; can anyone explain it?  And, is there any automatic way to set up routine backups of .olm files on an external drive isolated from the real time OS and whatever destructive entity may prey upon it as has just happened to me?