You will need
  • Laptop
  • Screwdriver
  • New battery
To begin you will need a new battery. To get it nowadays is quite easy: using the Internet, ordered on the official website of the manufacturer or a specialized online store. And you can go to one of the hypermarkets of electronics - even if it can't find required model of battery, you will be able to order it.
When new laptop battery for is already in front of you, release it from the packaging and check that the contacts that the battery will be connected to the contacts of the laptop, there was garbage and dust.
Flip the laptop and put it on a flat surface face down. Disconnect the dead battery.
If the battery is secured with screws, remove them using a screw driver.
Insert the new laptop battery. Usually getting the battery in the groove is accompanied by a click. If the battery is secured with screws, screw them back.
If after replacing the battery the laptop still runs out quickly, contact the service centre - most likely, it's not a dead battery and a faulty laptop.