You don't have to turn file sharing on. If you have file sharing apps, they will appear in a window under the list of apps in the apps tab of iTunes when your iPad is connected to your computer, and after you select the iPad in the sidebar.
Try something very simple. Quit iTunes, restart your computer, reboot your iPad and then start all over again.
Reboot the iPad by holding down on the sleep and home buttons at the same time for about 10-15 seconds until the Apple Logo appears - ignore the red slider if it appears on the screen - let go of the buttons. Let the iPad start up.