If your iPhone 3 is acting up, there are a few things you can do to reset it.

  1. If your iPhone 3 is frozen or won’t turn on at all, try pressing and holding the Sleep/Wake button and the Home button at the same time for about 10 seconds. This should force the device to restart.
  2. If your iPhone 3 won’t let you access any of its menus or settings, try plugging it into a computer with iTunes open and pressing and holding down the Option (Mac) or Shift (PC) key while clicking on the “Restore” button in iTunes. This should restore your device to its factory settings. ..