Now you need to set up your iPhone in iTunes. On the screen, you'll see two options: Set up as a new iPhone and Restore from a backup.
If you want to restore all of your settings (such as your e-mail accounts, contacts, and passwords) to the phone, choose "Restore from a backup." Select the name of your iPhone from the pull-down menu on the right of the screen.
If your iPhone has been particularly problematic, you may want to select "Set up as a new iPhone." This will prevent iTunes from restoring any troublesome settings to the phone, and you will be able to sync your data to it, anyway. But restoring from a backup can solve many problems, too, so you may want to try that first.
If you do choose to set your iPhone up as a new phone, keep in mind that the settings and other data you've added to the phone will be erased. All of the contacts you stored on the phone will be deleted, as will your text messages. You'll also have to re-enter some information, like passwords for wireless networks.
If you decide that setting your iPhone as a new phone is the best option, move on to step eleven.
If you want to restore your iPhone from a backup, you can skip ahead to step thirteen.