Laptop going off randomly and not switching on.

Hello,
my computer went off automatically. when i tried to switch it on, it made a weird sound and didn't switch on. I connected the power source and tried again, but still no response. I removed the battery and switched it on but there was still no response. when i give it time and try to switch it on, it switches on but goes off automatically, after a short while. what is the problem with my computer and how can.i fix it