Um... help?

[starsandsea]

Um, I've been having one or two problems with my MacBook's battery - it's starting to get old, and isn't charging quite to 100% and it's flashing between being charged and not being charged for about half and hour before it decides it is charged, but tonight it just isn't charging at all. I've tried switching my laptop on and off, the same with the power supply and I've even checked the charger itself, but I can't see anything wrong. I'm a little worried - will my laptop overheat if it doesn't charge? I just panic a lot over these things and my brother's out tonight, so I can't ask him... help me, anyone? Please? *is quite worried*