Had this with my Wife's Phone. The Power Button has a little black button attached to the top of the cable that wraps over the top of the phone. It had fallen off the phone so the power button no longer made the screen come on.
+
I had a phone where the phone was on, but the screen would not turn on. The Power Button has a little black button attached to the top of the cable that wraps over the top of the phone. It had fallen off the phone so the power button no longer made the screen come on.
I pulled the phone apart, and luckily the Little black button was in there loose still. I cut a piece of tape and stuck the black button on it before placing the tape over the cable, and putting it back into the phone. The phone screen powers on again when pressing the Power Button.
+
+
This may not be your issue by the description of your problem, but the title of your problem makes it sound like this could have been you issue.
Had this with my Wife's Phone. The Power Button has a little black button attached to the top of the cable that wraps over the top of the phone. It had fallen off the phone so the power button no longer made the screen come on.
I pulled the phone apart, and luckily the Little black button was in there loose still. I cut a piece of tape and stuck the black button on it before placing the tape over the cable, and putting it back into the phone. The phone screen powers on again when pressing the Power Button.