If you are using Steam, you will have to install the game into a different Library folder, or move the Steam install and game, such that you are not in a Windows protected folder, such as a Program Files folder, which is what Steam defaults to when it installs, and then it puts the Library folder below it, such that you end up with "C:\Program Files (x86)\Steam \SteamApps \common \Silent Hunter Wolves of the Pacific". The game runs fine there, but any modding you do will have its files set back to the previous state by Windows, so you'll get a mix of KSDII pictures, and Stock config files, which usually ends up crashing the game. Refer to
Moving a Steam Installation and Games for information on both methods. Once you have the game outside of the "protection" of Windows, then you can properly apply a mod. After that, then you have to clear the games "Save" folder, which generally defaults to "C:\Users \UserName \Documents \SH4", with "UserName" being what you log into Windows with, or use one of the multitude of short-cuts to your documents folder, and delete either the contents, or the entire "SH4" folder. The game will recreate the folder when you start it the next time, which will then bring in all of the information for the newly applied mod.
