Charging problem with connector

Hi!

I have a hp compaq hp 6715b.My problem is that it won't charge.I tried with 3 chargers which i know they work,nothing happens.In windows when i plug in the charger it shows a message that the power is not enough to charge the battery something like that.I disassemble the laptop and checked the connector.It shows 19v but when i press onoff switch nothing happens.Any solution would be appreciated.Thanks!