You can reset your iPhone and see if that works or not. Press and hold the Sleep/Wake button and the Home button at the same time for at least ten seconds. iPhone will automatically restarts and return to home screen. If it not restarts after holding the button for 10 seconds, hold down the Sleep/Wake button and the Home button until it restart itself.
Let me know if that didn't worked...Only click Accept after it worked. Best Regards, Ashik
Put your iPhone to DFU (Device Firmware Upgrade) Mode and restore it from iTunes. Follow the steps below;
Note : Put it to DFU Mode while connected to computer and also in DFU Mode your iPhone will remain blank. Let me know if that didn't worked..Only click Accept after we solved the problem. Best Regards, Ashik