PC won't power up

[Jonnibravo]

My son's PC has a ASRock live mix MB in it and in recent days the rgb light has been flashing on and off not in a warning light kind of way, but almost flickering. On occasions the PC would not boot and required you to turn the pc off at the mains before it would start even though the pc had clearly shutdown. Now it won't boot at all, sometimes it will boot on occasion, but it still needs to be switched off.