There are a few common reasons that a fourth generation iPod NANO may not start up, including the Hold switch and battery issues. In some cases, resetting the device can solve the problem.
There are a few steps to troubleshooting the most common issues that can be at the root of an iPod that does not start or where the screen remains blank.
Step 1: Unlock the hold switch
If the iPod has a Hold switch, check to make sure it is not in the locked position. The switch should be located at the top edge of the iPod and slides to lock or unlock. Sometimes it can help to simply slide it back and forth to locked and unlocked position again even if it is already in unlocked position.
Step 2: Check the battery
Plug in the iPod and turn it on after a moment. What does the battery indicator say? If the iPod's battery has a zero charge, the computer may not recognize it for a 30 minute period after it is charged up.
Step 3: Reset the iPod
If neither of the first two steps is the cause of the problem, try to reset the system. This will not delete or lose any audio or video files you may have saved and should restore it to working condition.
If none of the troubleshooting measures produce results, it may be best to consult with a professional repair person.