My battery says 0% charge, there is no x over my battery icon. The MacBook runs fine on corded power but dies as soon as I unplug. What could be the problem?
Is your MacBook a plastic one made before 2008? Did you buy a new charger for it at some point after 2008? If so, the issue could be an outdated System Management Controller (SMC).
For some reason, the SMC's in the pre-'08 MacBooks will not allow charging via a Magsafe cable made after 2008. It will run off of it, but it will not charge.
Fortunately, Apple has a patch. Download the SMC firmware updated located here, and your MacBook should start charging from the newer charger.
This can be one of two things.
Your battery could be dead. Check this by going to the system profiler and click on power, this will give you information on the health of your battery, and how many charge cycles it has done. Take a look at the 'Full Charge Capacity' if this is below 1,000 then there is a problem, if teh battery doesn't charge at all the value is likely to be at 0. If this is the case you can buy a new battery at http://store.apple.com/us/browse/home/shop_mac/mac_accessories/power
If the battery is in good shape then the next diagnosis to look at is your logic board (motherboard) if the connection has in someway been damaged, this can happen from a drop, overheating, burning out a connection, water, the list goes on. But effictly the battery isn't recieving power. Try using the MacBook without the battery in . if it is a logic board issue this can be expensive around £450 or $600