Laptop troubleshooting…

I have a HP dv6000 series laptop. from last few days i was suffering from battery backup problem. When my laptop runs on battery it had been discharging very fast and when it reached at 40% then it sudden drop at 5% and laptop went in standby mode. I was too much worried about it. HP laptop has a built in health-check software; i checked the battery with it; and it said my battery has a failure and it advised to replace battery with a new one. I was thinking what to do then i fully discharged the battery and recharged it fully. i did this 3 times continuously then battery seems OK. but after one day i faced same trouble then i see a new problem; when battery is not taking charge but power light indicates it is charging. Then my boss advised me to remove the battery from laptop and work without batter for a while. and after plug in the battery it is taking charge now. but not sure about the battery. May be it is the end of this battery. My boss is getting me a new 12cell battery. I have now a 6 cell battery. Wish me good luck for new battery.