Why is my laptop shutting down by itself

@osmopatrice you need to determine why it is turning off. Could be software related or hardware related. Windows keeps an Event Log file that keeps a detailed record of your computer system. You want to take a look at that first. Depending on your version windows, there are different ways to find the event viewer. You can always post part of the event viewer as a picture with your Question. that way we can see what you see. Adicionar imagens a uma pergunta já existente

If that does not display anything which may lead to the shutdown, then you want to check your power supply, your battery etc. You have to make sure that it is not a thermal shutdown, meaning that your computer gets to hot, it will shut down. Make sure that you have enough airflow. Don't use the laptop on a pillow or anything else soft since that can occlude the air-vents.