Yesterday I had the latest official version of iTunes installed. Before I went to install iOS 5, I also downloaded and installed the latest iTunes 10.5 beta. Unfortunately I didn't backup the phone again prior to installing iOS 5. Now that it has been installed, I notice that all of my SMS messages and notes are gone. I don't see any indications that the backup is still on my computer. So when installing the latest iTunes beta, did it erase my backup on my Windows laptop? Is there any other way to possibly retrieve my data?