Dell 7348 plug in power cord doesn’t charge and computer can’t start up

The AC adapter LED lit is on when plugged in power outlet, Once I plug into computer, the adapter the light goes out. Next I press the power button with the adapter plugged in and nothing happens. Then I try with the adapter unplugged and the Adapter LED lit on again. I then disconnected the AC adapter, removed the battery, and held in the power button for 60 seconds and no luck. The adapter light disappeared again when the battery is disconnected and the AC adapter is plugged in. I have tried different power cord, it happened the same thing. Does anyone have any suggestions on what could be the problem, could be the motherboard or battery issue?