Doing what you do of having a full battery and allowing it to run down completely usually does the trick.
This problem is sometimes caused by the power configuration in Windows and sometimes by the battery reporting. As long as the battery isn't damaged or "worn out" then a refresh of the battery may correct the problem.
After using the battery for 2 hours,it showed 50% remaining but 'time remaining' was only 30 minutes. and as I said, windows battery meter is not an accurate tool.But in real, it will last much longer than that.4 hours.So i m sure there is a problem,otherwise i know very well how to understand the 'time remaining' as i have been using laptops for quite a long time.But when i turn on my old laptop,it shows 2 hours and later on,it keeps reducing depending on the tasks i do.But in this new one,as soon as i turn it on(even before opening any application),it starts showing 1 hour 30 minutes.Old batter is fine, it just doesn't hold a charge for longer than about 30 minutes. Hi I own a laptop repair company and we come across this a lot... Even when the battery is fully charged it shows the battery charge status at 0%.From other message boards this seems a common problem which Microsoft have recognised but don't seem to have put it right!Old batter is fine, it just doesn't hold a charge for longer than about 30 minutes. Does your laptop have an indicator light that also shows that there is a battery issue?I have just bought a new battery for my Asus A7U and the error message no battery detected comes up as well as the battery not charging. The supplier has changes the battery for another one and the same is happening. Are you sure the battery is the correct type for your laptop? Usually, aftermarket parts are fine, but if it's not working, it maybe the manufacturers fault. If that's the case, ideally you could get someone to test the output voltage on your AC adapter, but the most probable scenario is that the motherboard needs to be replaced.