IOS5 update erased all my app data AND all backups made prior to update...

Question

I know there are lots of people who have had similar problems when updating with a PC but I still can't find a solution.  So maybe there isn't a solution.  But my question is this: I made two back-to-back backups of my ipad onto my friend's iTunes (on his PC).  Then I sync'd.  Then I updated to iOS5 (which did a final backup before it updated).  When I restored, I was asked for a password -- when I never encrypted it with a password!  So I tried every password known to me (on my iPad, iTunes, etc.) and I tried every password on my friend's PC.  Nothing worked.  Eventually, iTunes stopped asking me for a password.  But whenever I tried to do a new restore, it would only give me the option to restore from backups made AFTER the iOS5 update.  I have no idea what happened to the several backups I made BEFORE the update.  What a pain!  Does anyone have any ideas?  I spent two and half hours on the phone with Apple Care last night.  They had no ideas whatsoever.  They kept telling me that my backups must have been corrupted.  I don't know... feels like a cop-out on their part (even if they are right...).  Any help would be greatly appreciated.  Thx guys.
P.S. Oddly, my iBooks content remained in tact despite the fact that all other apps were gutted of content).  And the native Notes app was also gutted of content.  I guess from now on I will have to loop Dropbox into everything.

Answer 1

I did look for the backups.  The only backups showing are the ones that I made after the update (when I was sync'ing in a desperate bid to try to recover my app content).  I did not turn off auto-syncing beforehand.  In retrospect, I obviously made a mistake of some sort.  At the very least, I should have made redundant backups, etc.  But to continue, No, I am not sure that the backups were successfully made.  But I am totally sure that the PC went through the motions of making at least two backups -- it said as much on the screen.  Also, when I foraged through all the newer, hidden files on the PC, I found bits and pieces of the initial backup I made, all time-stamped correctly.  I found the contents there for my iBook app, and I found backups of most but not all of my other apps (but not their content).  So definitely there was some sort of general backup that took place.  Just not the full backup/s I'd hoped for... Yes, iTunes did warn me that the iPad would be erased, but I assumed that was all part-and-parcel of the iOS5 update.  That said, the first time I got the warning, I stopped the update and backed up (and then sync'd) again, just to make sure.  Only afterwards did I go through with the update. 
I am guessing there is not much I can do anymore at this point.  But thanks for the feedback and, if you do think of anything, or anywhere else on the PC where I could try to look for the backups, please let me know.  Thank you!  Your help is much appreciated.