iPhone 4 restart when the lock button is broken My iPhone 4 suddenly just crashed and turned itself off - without any Message. I've tried to plug it in to my PC, but I can't get my iPhone to power up. The Apple logo appears for about 3 seconds, and then it disappears - it happens consistently. My lock button is also broken, so I can't reboot it.

How can I power the device up?
Plugging a phone into a computer or power source via the usb cable will power it on, even if it is off – your phone is in need of repair or replacement.

I've seen the apple logo appearing for a few seconds and then phone dying several times with dead phones. I've fixed countless phones, but I don't have a concrete answer for this problem other than it being related to the motherboard in your phone and the solution is a replacement (replacement part more than value of the phone)