Laptop shutdowns when the charger is unplugged

Hello, I have this HP laptop for about 1-2 years old. I used it one week ago and after I used, it suddenly shutdowns because the battery is empty and there's no electricity that time. 1 week passed and i remember to charge it but when i accidentally, pull out the charger from my laptop, it suddenly shutdowns. Why? And it won't turn on without the charger plugged in and says 0% battery (plugged in, not charging) what should i do?

Please give me solution asap. Thanks!