[Pisces]

Ok, let's see if this helps you handle editing the registry part:

I don't know what Windows version you are using. So there may be some differences in the way you should be doing this. Just say when you loose track.

1: Open start menu and start typing "regedit"
2: Rightclick in the application that is shown "Regedit", and run as administrator.
3: Provide administrator password if User Account Control asks you for it.
4: In the tree-structure on the left unfold:
Computer\HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\S onalysts Combat Simulations\Dangerous Waters
(I presume you have a 64-bit install of windows. If it's 32-bit then ignore the "WOW6432Node" level)


5: Right-click on the "Dangerous Waters" key (looks like a folder), choose menu option Export
6: Store the registry key in the folder of the DW version you initially installed. Give the file a descriptive name of the install. That is the original install. Not of the derivative DW install.
7: Close Registry Editor.
8a: Locate the original DW folder with Explorer. Make a copy/paste of it for the 2nd DW game you want to mod or whatever. Rename the folder to represent the DW version.
8b: In the copied DW install rename that copy of the registry file with an appropriate name for the intended DW derivative. (Keep the .reg part at the end intact)
9: In the new DW folder edit the exported registry file with Notepad. Do not double click on the file, but right click instead. Use Edit. Or "Open With" and choose Notepad in the wizard that follows.
10: After Notepad has opened with the file. Only in the various lines with "Install Dir" or "InstallPath" edit the folder paths to the new DW install. Keep the double backslashes intact.
11: Save the file.

Whenever you want to change to another install to play the game: Double click on the registry file in the folder of DW that you want to play first. You may get asked for administrator permission. After this you can modify the derivative DW folder to your heart's content.

To play the game in the original DW folder just execute it's own registry file to reset your system's registry back the way it was.