The power jack is the part of the laptop that connects the AC adapter to the laptop, allowing the laptop to be powered on. If the power jack is broken, your laptop won't power on and you'll need to replace the power jack.
To fix a laptop charger port, you need to first identify the source of the problem. If the power jack is connected to the motherboard, you can easily remove and replace it. On the other hand, if the power jack goes soldered to the motherboard, you'll have to desolder it and replace it with a good one.
Basically just remove every screw you see and be careful not to damage any fragile Reventon or something else now that we've got the laptop apart.