Help with CPU! i will award best answer!!!@!?

Well i am planning on buying world of warcraft WOTLK on thursday and i check and my computer has the requirements for the game but... when i play the previous games with sound my CPU will shutoff but its not laggy. So i took off sound and my cpu never shut off again. But i am wonder once i get WOW WOTLK will it shutt off with out the sound (since its a bigger game) if so how can i prevent it?