The laptop doesn't turn on

Hello,
I have an acer aspire 3680 and it doesn't turn on. When the battery is in and the power cord is plugged in there is a green light on the battery, but when I take the battery out and only the power cord is plugged in there is no light.
I have tried to take the battery out and unplug the power cord, hold the turn on button for 30 seconds then plug the power cord in and tried to turn in on, but nothing happened. Also checked if RAM is loose and it's not.
Can anyone help me please.