It's only rated for 300 cycles, about 18 months if folk use the battery but I understand folk loathe the idea you must slip in a new good battery to answer the question.
I happen to have a weird problem. Last evening I peacefully worked on my computer, I plugged in the AC adapter earlier to have my Lenovo G560 laptop charged. When I saw its battery is fully charged, I simply unplugged the AC adapter as I always did, but this time the laptop switched off immediately. Since then, I can't power up the laptop from the battery or charge it (the battery LED on the front just blinks sometimes, or does nothing, most of the time.
I tried the reset thing by removing all power sources and pressing ON/OFF button for some time, but nothing happened. Does this mean the end of my battery? Thank you for your answer.
BTW: The laptop works perfectly with AC adapter on. The battery type is Lenovo L09C6Y02.