my i phone 4 just blackedout

[iMore Question]

I received 3 videos in the morning and downloaded them for viewing after 4hrs I received a call and I couldn't hear the caller as I dropped the call my screen blacked out until now. what can I do to fix it?

 

[kch50428]

Press/hold the home & power buttons until the Apple logo appears... let go of the buttons... let the phone boot.