Why is my computer turning off?

Hello,

So when I push the power button located on the top right, the light goes on (button), all the indicators lights below the trackpad are turning on however after 1 second, the whole computer shuts down. During those one second, my hard drive is making one very light click sound, only one. I tried to open it and blow air to clean up the computer of all the dust. It did work for about a week but then the same situation came up again. Now even if I clean up the inside, it is the same.

Thank you in advance.