IPhone 4 won't turn on - 1

Ok so my friends iPhone 4 won't turn on we tried restoring it, rebooting it with the home button and power method and nothing has worked! Could there be something wrong? Any other methods? 10 Points for best answer!

Personally I would ask someone with alot of experience in electronics. Go to were ever you bought the phone verison wireless, t moblie they can help you or best buy. They are very good with fixing stuff like that.

Well, lets see…
1) out of battery, plug it into a power source
2) just leave it alone for a few seconds.sometimes it would automatically turn on.
3) Did she drop it in water or leave it out in the sun?
water: rice treatment
sun: let it cool down