Okay so, weird situation. When I plug in the mac, the green light lights up for like 3 seconds and then it just stops. If I push (and hold) the charger into the wall, it works fine. This is my sister's computer, and she's gone through like 3 chargers, so I don't know if it's the charger, but it seems like it may be. I think she's tried other chargers and they haven't worked either. Does it have something to do with the mac or is it definitely the charger?