If anyone is having trouble starting a game (game refuses to start after selecting difficulty and so forth). You don't have active profile.
* Make sure the following folder exists: ...XP: C:/Documents and Settings/USERNAME/Local Settings/Application Data/Activision/CoDWaW/players/profiles/ ... Vista/7: C:/Users/USERNAME/Local Settings/Application Data/Activision/CoDWaW/players/profiles/ * Add profile folder there, choose whatever name you want (e.g. "Default"). * Add active.txt file there (in profiles/), and add the name of your profile folder in it. * Start
Note that the Local Settings folder is usually hidden.