New proximity Sensor not fix dead power button?

I got a iPhone 4s cheap and the power button did not work it would just stay down and not come up, it did not have any click to it. So I replaced the proximity sensor the cable and earpiece and everything. After I put everything back together I tried to turn the screen on with the power button it would click and come back up but it still does not light up the screen. The phone works fine besides the power button. What do I do?