Tower shutting down on just one game???

[EJSLP]

I wanted to play sniper elite v2 about 15 minutes ago but about 5 mins into a mission my tower is shutting down and re-booting? tied this a couple of times to make sure it was not a glitch or whatever.
I checked other games,played part of a movie from youtube and no problems at all?
how can it be just this one game which played flawless up until today?
any idea's cause i am:'(

 

[sm625]

Is it always the same spot in the game where this happens?

 

[EJSLP]

Is it always the same spot in the game where this happens?

seems that way? what i did since posting this was removed the game from my drive and re-installed it from steams library. hopefully this will be a fix

 

[BadThad]

Either: buggy game software, over-heating or a bad power supply.

 

[EJSLP]

Either: buggy game software, over-heating or a bad power supply.

buggy software wins,
I deleted it from the drive then re-installed it,seems to be ok for now
but stil i had never heard of a game shutting down a pc before