Hello guys, new member here and looking for some help. I have an iPhone 4 that's power button is unresponsive. I searched around here and found many posts about this; however, mine is much different. My power button actually clicks and seems to structurally work fine, but once pressed there is zero response on the iPhone (sleep/on/off). Could the proximity sensor need changing? Or am I looking at something else here? Any and all help is appreciated! Thanks.