Call of duty 4 working key

here is a working key code for call of duty multilayer i played from it several times about 4hrs but now its saying the key code is in use so i deleted and the game and copied it back to my lap it worked but again its saying key code is in use but this code sure worked for me for a while and m satisfied with it.

PJTY-22LT-YLWD-MUGU-D87E

If it works for u then smile and enjoy