My MacBook is old and out of warranty, but it still works pretty well. I woke up on Tuesday morning and it was fully charged. I went to work and was using it. The battery got down to 11% and I went to put it on the charger. When I plugged it in, nothing happened. The light didn't go on and it eventually died while plugged in. A few days later, the battery is still dead and it is still not registering the charger. What can I do to resuscitate my computer?