My MacBook air won't take the charger from its charger. Overnight it went from working to not working. The charger barely lights green when I plug it into the laptop. I remember I rolled over the cable with my desk chair, would that be enough to screw it up? Thing is, I'm planning on selling my MBA and I want to make sure that the charger hasn't messed up the laptop. Don't wanna sell a faulty product. Can anybody tell me what the barely lit green led means?