If your laptop refuses to charge, it's not always the fault of the battery, especially if it was working fine up until that point. In that case, it is more likely the fault of the laptop power adapter, the cord responsible for providing energy to the battery. It is in charge of converting the wall's AC power to DC, power a laptop can use. This adapter for the HP 740015-003 741727-001 HSTNN-DA40 is a replacement adapter that works as well as the original, giving you a full charge as soon as possible so you can take your computer wherever you want. Its small profile is travel-friendly, so you can bring it along trips no matter how short or long.