I can see that "administrator" thing happen if you have your games installed where the EA app wants to put them by default. However, I had all my Origin games installed on a different partition, which means that was never necessary. When I was forced to switch from Origin to the EA app, I just told the app to use my old "Origin Games" folder for its games. It accepted that, noticed that I had all my games there, and that was it. I didn't need to reinstall anything. The whole process took about two minutes (not counting the time it took me to backup The Sims 3 in case anything went wrong).
Not that there wasn't any hiccup. When the installation of the EA app was done, it told me that something went wrong. It didn't tell me what went wrong though, and I haven't found out yet, because everything seems to work just fine. Maybe, that's the error :p .
