Why my HP laptop shuts down when I unplug it from charging?

Hi guys,
I want to know what is the problem with my HP laptop i is almost a year I bought this HP laptop and it was working good till now, but suddenly it started to hang up and when I unplug my HP laptop from charging it shuts down. I'm really worried with this problem please tell me how to fix it or do I need to take help from HP support person.
