Computer randomly shuts off

[Lustlife]

Whenever my turns on his computer it instantly turns off and everyone once and a while he will get this error msg. 

[Lustlife]

[K1ng]

not seeing an error just hdd smart is disabled.

Overheating or bad power supply is most likely the cause for instant shut down. If the pc is off for a long time will it get further in boot? if so it is 99.9% heat related.
Only other thought would be if he Overclocked the CPU too far and caused an issue there or the mobo but that is much less likely.