Iphone 4 won't turn on + has battery?

My iphone 4 isn't turning on, its been working all day, and now it won't turn on, its been plugged into the mains adapter, the two buttons have been pressed for over 2 minutes and nothing has happened, can i do anything at home or do i need to go to orange or would i need togo to the apple store?

Try holding the bottom button down by itself if nothing happens hold the top button down by itself, still nothing? Hold both buttons down at same time, try not to get frustrated and stay calm, if nothing works take it to shop

hope this may help