I have not done this as of yet. I will do it right now - and see if this fixes and resolves the issues. The battery is a brand new one from the "Laptop BatteryStore..
UPDATE - I have downloaded and install the latest BIOS F24 from HP - installed and rebooted the system. Unplugged from AC and the lap top ran for appx 20 mins or so - showed the battery level at 100% when I unplugged from AC - and throughout the next 20 mins only showed it be reduced to 96% - than the Lap Top shut itself off! Only way to get it to power up - was to remove and re-install battery - came back up and lasted 5 mins and shut itself off again? If I plug in the AC power the unit will power right up... However - it will not power up with just the battery unless I remove it - and re-install it...
i think you have to go for compaq service center. tell them your problem. there is something mistake in your brand then. as you told b4 that when you buy that at that time also you were facing the same problem. so it means your lapi might be faulty.
Update: Purchased new HP 12Cell Battery from local retailer (Fry's Electronics- Fountain Valley, California). I installed the battery - and waited until it had a full charge. Powered the Lap Top on - and have had no problems from this battery - Apparently the battery that I had purchased from LapTop Battery Store was bad.