The last time I synced my iPod Touch (4G) was on a now-broken MacBook Pro (dead logic board), and when I'm trying to upgrade it to iOS 5 on my replacement laptop it's telling me that it'll erase all of the content on it unless I do the upgrade on the computer that I normally sync with (which isn't possible). I have a Time Machine backup of my old laptop, but for some reason it doesn't have the iTunes library xml file, so I can't convince it that it's the same computer. Am I stuck wiping and restoring everything, or is there some other way to go about this upgrade that will preserve the contents of my iPod?