keeps crashing

[Bunnn]

when i play half life 2 or cs or far cry

when i start playing my computer always crashes for no reason
how do i fix this?

 

[Cdubneeddeal]

How much do you have your card overclocked to?

 

[Bunnn]

i tried to set it at no overclock and it still does that....

 

[Bunnn]

hhelp

 

[Bunnn]

ttt