Try going into download mode. If that works then it might need a reflash. If not then you might have to send it in for repair if it's still in warranty as it sounds like a hardware fault.
Firstly, power off your Samsung Galaxy S4 totally and after that remove its battery and keep it out around of 10 seconds. Secondly, Re-insert the device’s battery back in its specific location. Thirdly, press and keep holding the following combination of buttons: Volume Down, Home and Power buttons simultaneous. Now, when the ‘Warning!!’ message will be displayed release the buttons. After you released the buttons, press Volume UP button, for confirming that you want to enter into Download Mode Menu. Your Samsung Galaxy S4 device will display an Android logo colored in green, and an additional text message with the ‘Downloading… Do not turn off target’ text message under the green Android logo.
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