1. Power down the iPhone anyway you can.
2. Connect it to the computer with the usb while holding down the home button.
3. Keep holding until the it says it is in recovery mode.
4. Done
The power button is on top of the iPhone 4. You hold down the button to either turn the phone on or off.
Press the button on the top of the power butter.
Try resetting your iPhone. Hold Down the Home Button AND the Power button at the same time for 30 seconds
No
Settings>general>accessibility>assistive touch>device>lock screen.
Try resetting your iPhone. Hold Down the Home Button AND the Power button at the same time for 30 seconds
First you have to "jailbreak" your iPhone and install Cydia.Then you must install a program called "iFaith" to save your "SHSH Blobs".Then open "iFaith" and press "Save your SHSH Blobs".Then you have to download the "iOS" that you want do install.Then you have to download and install an older version of "iTunes" you have to download this version "11.0.5".Then when your download and isntall are finished open "iTunes".Then you must turn your iPhone in "Recovery Mode" by holding pressed "Power and Home-Button" for 10 seconds,after 10 seconds you have to release the "Power-Button" and hold pressed "Home-Button" till a text appears on "iTunes" saying "There is an iPhone in Recovery Mode" the press "OK".Then go to "Restore" by holding pressed "SHift" and find the saved "SHSH Blobs" and press it.Now your iPhone begins restoring to the iOS you want.
Hold down the Lock/Power button and the home button simultaneously for a few seconds until the "slide to power off" slider bar comes up. Swipe the red slider button across the bar. The iPhone will turn off. When the screen goes dark, hold the Lock/Power button until the Apple logo shows up.
Simply press the power button (on the side of the phone) and hold it for a few seconds. The iPhone should then boot.
Try holding the power button and the home button for roughly 10 to 15 seconds. It should restart.
this is what happened to my iphone and i figured something out. what you do is go into settings, general, accessibility, and click assisive touch. put it on and in a few seconds a little circle will pop up on the bottom right corner of your screen click your home button and when your at the home screen that circle will stay there. click on the circle and if will give you options if your home button is broken you can click the home button in options but for the power button click the little ipod then click lock screen it will lock your screen without the power button. Also is you would like to power off your screen hold down the home button and the lock screen button and it will ask you to power off your ipod. if you want to power it back on you will need to plug it into a charger. hope this helps :)
The iPhone battery was built-in, it is not so easy to reaplace it without open tool. But there are some extend power for iPhone, you can choose them to get more power.