It doesn't happen very often. It happens only when I am playing any game. Or starting a game. Or else it's working fine. My processor is Ryzen 5 3400G. Mobo B450M Mortar Max and the PSU is a chinese 200w which comes with the casing. I don't have any dedicated GPU. It just suddenly goes off, no pop ups or anything. Just the screen goes black.
Not any No lights or fans turn off inside the PC.