That's the Li-ion surprise, probably the cell voltages are too low, thus the charger wont charge. You can try booting into the BIOS and see if there is a Battery learning tool in there, but my guess is that you need a new battery. I would go to a larger retailer on the internet, what you want is newly manufactured batteries not old ones. these li-ion batteries age from the date manufactured, keep them 60-75% charged and they should last for more than 2-3 years. Throw the battery in the refrigerator next time you store it.
Cheers