The laptop is completely dead. When you plug the AC adapter and press on the power button, nothing happens. The laptop has no signs of life at all. None of the LED lights is working.
1. AC adapter failure.
2. Power jack failure.
3. Motherboard failure.
Possible troubleshooting steps and repair solution:
1. Test the AC adapter with a multimeter. It’s possible that you have a failed AC adapter. If you don’t have a multimeter, test your laptop with another known good AC adapter.
2. It’s possible that power jack (socket where you plug the AC adapter) is broken. Remove the motherboard and take a closer look at the power jack. In some cases you can fix the jack by resoldering it on the motherboard. In other cases you have to replace the jack with a new one.
Using a multimeter, test if the power goes to the motherboard through the jack.
3. If replacing the AC power adapter and jack on the motherboard doesn’t help, most likely you have a bad motherboard. Replace the motherboard.