Sounds like over the last two years you have ran the battery dead almost every time before recharging and/or left it discharged for too long. This is the worst thing you can do and shortens the battery life. Li-ion's grow crystals in cells that are dead for extended periods of time. You will have to buy a new one but always keep it charged up and charge after ever use. About 4 to 8 times a year you should run it dead (and immediately recharge) to keep the internal monitor calibrated.