Restored on 2nd PC, original says it will erase everything just to restore music.

Needed to restore, upgrade to iOS5 clean install, and Win7 PC wouldn't restore, USB errors. Restored on Mac Book Pro OK. Just iOS5 no Apps, Music, Photos, Books, etc, just basic install. Went back to Win7 PC and installed all Apps, Photos, Contacts etc. Then when I tried to load Music from iTunes, non-DRM, it says it was synced with another computer and it will errase everthing!!!! The tutorials I have seen show iTunes saying it will only replace the Media, not erase the iPhone. Will it erase everything or just the Media??????


HELP, I don't want to have to set up all my Folders again, it's a PITA.:(