It may not be the battery at fault. Other causes include a fault in internal charging circuit, and bent pins in the bit that connects to the battery when it is slid into place. Ask a tame electrician to try the battery on a meter, and if there is still juice in there then suspect the connections, if it is totally flat suspect the charging circuit or even the battery itself. I have had a Acer laptop for 5 years now with the same battery and it is still giving good service.
It sounds like an open circuit in the battery circuit. That can include the charging components, connections or battery internal wires. All of these will give symptoms of no power and no charge light on mains.