How do you update cod mw3?

Heres how download punkbuster (ifyou dident already at www.punkbuster.com and search in google patch v1.7-1.6 and go to gamershell.com and download it from where u live at usa,Canada,exct. and do this for cod4 and waw and install it and there you go cod4 fully updated for the PC (note:patch does not block private servers that are hacked it updatesthe maps.)