my i phone 4 screen went completely black and screen will not work but i can screenshot and other buttons vibrate and make a sound the screen just dosent respond.

my home button was not working and I was in my settings looking for the advert touch or whatever it is called and my phone went completely black. al the buttons worked such as screen shotting (it made the sound) and turning on my ringer, the screen just didn't respond. I left it alone and plugged in over night and it hasn't done anything different. I also plugged it into my computer and it still did nothing. what can I do to resolve this problem?