Matthew says that he's been having issues with a used Apple MacBook laptop maintaining a charge. Leo says to change the battery. If that's an issue, then he can move to the charger itself, and they fail. If it's not the power adapter or the MagSafe, then look to the cords. Outside of that, it will point to the circuitry inside. He can download Apple's diagnostic software, it's been leaked online. But if there's something inside, Apple will require replacing the logic board, and that's nearly the cost of an entire computer. But at least take it into the Apple Store and pay for the diagnostic. They'll tell him what's wrong. He could also plug in the adapter without the battery and see if it powers on.