Hello and thanks for your question, my name is ***** ***** i will be assisting you today,
Please try to reset it. It may have a bad software OS loaded and we can just replace with a new copy.
Make sure you backup your data (contacts, documents, photos, ect...)
Press and hold the Sleep/Wake button and the Home button at the same time for at least Ten seconds until the Apple logo appears. Release the Buttons.
If the problem persists pleaseTry a Restore :
1.Connect the device to Your computer and open iTunes.
2.If the device appears in iTunes, select and click Restore on the Summary pane.
additional information : http://support.apple.com/kb/HT1414
3.If the device doesn't appear in iTunes, try using the Steps in this article : https://support.apple.com/HT201263 to force the device into Recovery Mode.
Make sure you have the Latest Version of iTunes Installed on your computer : www.itunes.com/download
Once you have Recovered your iPhone Device Re-Sync your Content or Restore from the most Recent Backup :
Restore from Backup > http://support.apple.com/kb/ht1766
Let me know if you need further assistance