How come my laptop has to be plugged in to power on

Hi,

What does the battery charge state indicator tell you when the laptop is connected to the adapter?

If it says charging and then eventually reaches fully charged or even if it says fully charged and then the laptop doesn't work when on the battery only then in all probability the battery will have to be replaced.

Even rechargeable batteries have a life span.

Replacement batteries are available online, just search for HP Pavilion dm4-2015dx battery to find a supplier that suits you best.

Remember that if you do get a new battery, to fully charge it before first use. Do it with the laptop turned off to decrease the amount of time that it will take.