In iTunes on your PC, click "Edit">"Preferences" then click on the "Store" icon. Now uncheck all the boxes "Music", "Apps", and "Books." That should stop all the apps and music from jumping across devices. Whenever a new version of iTunes is detected it will ask you if you want to automatically download. Be sure to click "No" when you see this message. You may not have noticed it when you downloaded the new version recently.