Built a computer 2 months ago, standard 600$ build. started suffering power failures in the form of instant shut downs followed by 1-2second on/off switching. added heatsink to cpu and the problem seemed to be fixed but started running games and game froze and then instant shutdown occured again. now computer can run basic chroome but streaming or games will cause power failure.
More aboutheat issue
if it switches off like the plug was pulled from the wall then the issue is with the power supply .