RockmasteR

what do you mean by advertisements?
you mean when videos of THQ plays before the game?
are you able to play the game at all? is it slow?
also post your full PC specs
did you try any game besides DOW 2? (I mean now, when the game lags) to see if it is from the game or from your PC
download SIW from my sig and open it
under hardware, choose "sensors" and check your temps in idle mode
play the game for 10 minutes, minimize it and check the temps again
please post both temps here (when idle and under stress)