It could be that your power adapter is not providing enough power to your computer for it to charge the battery. Or your power adapter is somewhat broken (like the connector) and isn't conducting enough electricty and isn't able to charge your computer. Or loads of others possiblities. What I'd suggest is see if your computer charges with the power off, and if it doesn't, see if you can obtain a new power adapter or chord.
yo ucouls use a multiMeterr t ochek and see if power adapter is working ,if you dona't have a multimeter you could take your power adapter to a repair shope and have them check to see if its putting power to the TIP