I NEED HELP REGARDING MY IPHONE HANG UP....
- press the home keys and power button simultaneously for about 5 secs... it should reboot
- Sometimes iPhone hangs up at dialer screen with Process ring working in center. There is no need to wait and drain the battery. u can simply press Home key and power key at same time and keep it pressed for 5 sec. Your iPhone will switch off. Now press power key to start the iPhone and u will get rid of ur problem..
- it helps if you press home+power for 5 seconds. no need to backup and restore .. it will lock your iphone again :P