IPhone 4s won't find any Wi-Fi even after reset?

Since the update to 6.1.3 the phone won't find any Wi-Fi, we know the Wi-Fi is working because our iPads and other phones are connected to it. We reset the network settings, factory reset the iPhone and nothing worked. Is there any simple way of resolving this without taking it into the store?

Which is why you switch to samsung

Have you tried holding the lock button and home button together for ten seconds until the apple logo appears then releasing the buttons.
This resets the iphone and can sort out loads of little problems like what you are experiencing.
If this fails though you could plug the phone into the computer and do a full restore this should be a last resort but should sort the problem if thats all you have left.