|Whether the battery is working properly or not, when it is plugged into AC power it should work anyway. It is likely a bad power adapter, which is not working, and once the battery ran dead, it no longer charged due to the faulty adapter. That is the more likely thing. So make sure the adapter is firmly plugged into the square box (transformer) part and into the laptop. You can test the adapter. Also you do not want to buy a universal adapter, you want the one made for your computer. It is likely under warranty? The battery usually has a couple of slide tabs one to "lock" it into place, so make sure the lock is not, and then slide the other clasp and pull on the battery. It should work without the battery, straight off the power adapter cord.|
To err is human but to really screw things up, you need a computer!