I got it fixed last night with a very manual process. I went to sync, wrote down (screen shots) all calendar entries and address book entries that it said it needed to copy to the phone from the PC. I then cancelled the sync and manually deleted those entries from the phone. I then re-synced and let it copy them over. And, now I don't have any duplicates!
I was thinking about it afterwards, and this is what I think was happening. I saw the PC had 880 or so calendar entries to copy (when processing the sync with the green bar), but it was only going to sync those that are in the future...not past-due stuff. So, when I did the Backup/Restore Advanced clearing of the Calendar, it only saw 67 items to copy. Last night, I thought the Desktop Manager was messing up becasue that number (67) didn't change from before I cleared the Calendar. Oh well. It's working now.
By the time I manually deleted 67 calendar entries one at a time scattered all through the year, I realized I had removed all calendar entries by hand. Even though my calendar database said it had 118 entries per the Backup/Restore Advanced part of Desktop Manager. Most were birthdays that happen every year, so maybe it was copying those for the next 2 years (67 x 2 = 134), but not all of them because I only had 118, so maybe not the ones in Jan or Feb that have already past...just going trhough Dec 31, 2010???
Advice for those that are trying to upgrade the OS to version 4.5...or any other version...I would suggest doing a battery reset first. I'm not sure if that would have helped or not, but it's something you have to do first and cannot go back and do later once you have backed it up and gone through the upgrade.
My wife's phone did have 2 e-mail accounts set up with only one of those on her PC to sync with. All BIS...no BES...no redirector.
There were only a few address book issues, so I did those manually too, but that was easy compared to the calendar stuff.
Anyway, like I said...I got it to work.
Thanks for the advice!!!