Call of Duty Modern Warfare 2 Graphic Problem

I have completed the ACT I of the game and now the graphics are irritating me for a while.Suddenly while playing the graphics becomes fluctuating[blinking] and then sometimes it goes off by itself and sometimes blue screen comes up and it restarts the computer.
So is it posssible to stop this??
Answer #1
1. did you use the latest driver update?
2. did you overclock anything?
3. did the game original or not?
Answer #2
said,

1. did you use the latest driver update? 2. did you overclock anything? 3. did the game original or not?
First of all i am using the latest graphic driver ,didn’t overclocked and about the game i have downloaded from this site and of skidrow.