well, have you tried leaving it on charge for a few minutes? if that doesn't do anything, hold all buttons down at the same time '''until logo appears on the screen'''. (this applies to all phones). take it to a phone shop/contact a phone shop, to see the problem or get it replaced. if you don't want to do that, the case might be that the phone is completely flat in which case it certainly wont turn on and the screen wil be completely black which the solution is to charge it. hope this helps,, it worked for me:)