just put it in the call of duty/ main/ folder and run it
everytime you start game 
then use ctrl/shift/end   
to minimizes the game
then use ctrl/shift/home 
to go back to game 
it works a dream saves stoppin game all together 
enjoy :)
i made a shortcut on desktop so i could run it b4 startin call of duty

i can't take any credit for making this but i found it on a web site for soldier of fortune 2 and tried it with call off duty and it worked