Connect the phone to the computer it is synced with and restore. You don't need to use DFU mode as stated earlier. You'll need Recovery mode. If you don't know the passcode or if the phone has never been synced with that computer, it will give you the option for a full restore to factory settings. This can be done on any computer with iTunes, but she will lose all of her photos. If she has an iTunes or iCloud backup, she can use it and it will restore everything, including her pictures. She can set up automatic backups, Photo Stream, or sync the photos to the computer to prevent this in the future.My daughter forgot the password on her iPhone 4s, does anyone know how I can unlock it without losing all of her pictures and contacts. Please help.