I noticed that Zune may be my problem as well. I'll try uninstalling Zune and see how it goes. Thanks for confirming.
Hi Shannon,
It wasn't that easy for me (is it ever with MS?)
I first uninstalled ZUNE, and then (if you haven't rolled back yet) tried to delete the Zune files from my old profile.
(sorry this is from memory, some months ago now, but trying to help you through it.)
Then had to Google for how to delete those pesky files that ZUNE had left. Found solution (not just right-click and delete!).
Once I'd done that, I was able to RollBack successfully.
And then update successfully.
Sorry if this is a bit vague, and might be in the wrong order, but if MS won't help we have to try to help each other.