If your laptop won't turn on when it's unplugged, it is possible that the battery is the problem. Before attempting to fix it yourself, you should first try some troubleshooting steps to see if the problem can be resolved without having to open up the laptop or replace any parts. Here are some steps to try: Check that the battery is properly seated in the laptop. Sometimes the battery can become loose and this can prevent the laptop from turning on. Try charging the battery for several hours and then see if the laptop turns on when it is unplugged. If the battery is completely dead, it may need some time to charge up before it will work. If the battery is old or has been used extensively, it may need to be replaced. Most laptop batteries are designed to last for a certain number of charge cycles, and then they need to be replaced. Look up your laptop's model number to find the appropriate replacement battery.