Iphone 4s wont randomly shut down and wont turn on

I pressed the home button to look at the time & it randomly shut down . i pressed the home button several more times & still the screen was blank. This happened last night ( like 30 minutes after i updated to the newest iOS and downloaded beyonce's new album ) and i left it plugged in on my laptop for about an hour, then i plugged it in the wall , i tried a lot of things. i unscrewed the back and took the battery out for 3 minutes , even forced down my power button ( WHICH IS BROKE BTW ) , none of that worked . then i left in in the wall for another hour , still nothing . Please i seek assistance badly. i need my phone to call my dad everyday after school and i cant afford a new one.

Thanks in advance