My Phone won't turn on.

My Droid Incredible 2 won't turn on at all. I tried charging for a long period of time but still it won't turn on but the charging indicator functions and when I unplug it from the charger, the indicator just keep on functioning.

There's no physical damage on my phone. I just can't understand why it just won't turn on. My friend said it might have a software damage.

Please help me, I have very important documents on my phone.