my iphone has error 21 need help please.
my iphone suddenly shut down. i tried to press on button and tried to reset it but it wont work. when i charged it the apple logo appeared i left it for at least two hours. when i came back the apple logo is still there. then i tried reseting it. the connecto to itunes appeard. i cannot restore it. itunes keeps saying an error occured(21). and one more thing. when i unplug in from charger or pc it turns off. as if it has no battery/battery is doesnt work. is it the batt or the ios? please help
iPhone 4, iOS 5.0.1