Currently Being ModeratedFeb 18, 2012 1:15 PM (in response to Kcolbyj)
1. Why doesn't your power button work? Because it's broken
2. What should you do? Bring it in to Apple for an out of warranty replacement ($149) or find a 3rd party iPhone repair shop near you.
Currently Being ModeratedJun 2, 2013 8:48 AM (in response to Kcolbyj)
Apparently Apple chose to give the foil part of the button a little nipple like bit which raises it by less than a mm and this sometimes goes wondering around and this makes the external button sit that bit lower and not fully work. If you go to general settings, an then accessibility, there is a feature called "assistive touch". Turn it on, and you can lock your screen from there. If under warranty or enough money, you can take it a local Apple Store or send it in for repair. Hope this is helpful.