Start by checking your laptop charger. Frayed, or otherwise damaged cords can stop power from being delivered to your laptop. Most chargers come with an indicator light that lets you know when power is on. Be sure this light is on. If it is and you still have no power, try using a different charger. A universal charger will work for testing, but be sure to match wattage and voltage to your existing charger. These numbers can usually be found on a sticker attached to the charger or bottom of the laptop.  Wattage is usually indicated by a number followed by a “W”. Most chargers are 45w, 60w, or 90w. Common voltages are around 19v. You are safe to choose a new charger with higher wattage than your older charger i.e. 90w vs 60w, but never choose a voltage rating that is not exactly matched to your old charger. This can cause damage to your laptop.