Huge issue with my 64 bit Vista Dell and i-tunes. After months of ignoring itunes message to update, I did. Voila. No itunes at all. Tried uninstalling and installing it numerous times, using numerous instructions, doesn't work. What a mess.
My advice: DON'T download any itunes updates if you have VISTA and itunes is currently working. Otherwise you'll end up like me, not able to use itunes at all.
