Well, there's a lot of things you need to export in the registry, but there is an easier way to make ffxi run on a different machine other than the one you installed it on. Either way, I will list the Registry entries for those that know what they are doing with the Registry, but I would not recommend using this way if you are only mediocre at PC's. Scroll down further and I will explain how to move FFXI from PC to PC without having to copy much of the registry. Here is the list of all FFXI related Registry Folders(all subfolders will be exported automaticly).
[HKEY_LOCAL_MACHINE\SOFTWARE\PlayOnlineUS]
[HKEY_CLASSES_ROOT\FFXi.FFXiEntry]
[HKEY_CLASSES_ROOT\FFXi.FFXiEntry.1]
[HKEY_CLASSES_ROOT\FFXi.FFXiManager]
[HKEY_CLASSES_ROOT\FFXi.FFXiManager.1]
[HKEY_CLASSES_ROOT\FFXi.FFXiGameMain]
[HKEY_CLASSES_ROOT\FFXi.FFXiGameMain.1]
[HKEY_CLASSES_ROOT\FFXi.FFXiVersion]
[HKEY_CLASSES_ROOT\FFXi.FFXiVersion.1]
[HKEY_CLASSES_ROOT\App.PolAppCom]
[HKEY_CLASSES_ROOT\App.PolAppCom.1]
[HKEY_CLASSES_ROOT\POLCore.POLCoreCom]
[HKEY_CLASSES_ROOT\POLCore.POLCoreCom.1]
That's all the registry files FFXI needs. However, registering DLL's by hand may not be the best idea for some people, so let's do it an easier way. First, on the machine that does not have FFXI installed (but using it from external drive or something) add the Registry from here:
[HKEY_LOCAL_MACHINE\SOFTWARE\PlayOnlineUS]
just right click that name in regedit and export the file, then run it in the new windows. There are your configurations, such as resolution and install path. BTW, you may need to change the registry key for where ffxi is physically located, the drive letter might not match when you plug your external drive into a new pc. Just have to double check and change the installed location.
Now what you want to do is open up run menu (have to open Command console as Admin on Vista, otherwise it won't work for security reasons). Type and enter each line without the _'s surrounding it.
__regsvr32 "C:\Program Files\PlayOnline\SquareEnix\PlayOnlineViewer\viewer\com\app.dll"__
__regsvr32 "C:\Program Files\PlayOnline\SquareEnix\PlayOnlineViewer\viewer\com\polcore.dll"__
__regsvr32 "C:\Program Files\PlayOnline\SquareEnix\FINAL FANTASY XI\FFXi.dll"__
__regsvr32 "C:\Program Files\PlayOnline\SquareEnix\FINAL FANTASY XI\FFXiMain.dll"__
__regsvr32 "C:\Program Files\PlayOnline\SquareEnix\FINAL FANTASY XI\FFXiVersions.dll"__
except replace C:\Program Files\PlayOnline\SquareEnix\ with wherever your ffxi files are located, they don't have to be on the same harddrive as OS or anything like that.
That's all really, now you can play ffxi without having to reinstall and then wait for 5 hours for it to update. This is a way to back up ffxi. If you want to move it to a brand new harddrive without installation, you just have to copy the files over first and then do what I said above.
Just make sure that you copy registry and file at the same general time. ie do not update the files after you export registry, they will not match.
Hope this helps, if you have any questions I can write this in more details.
P.S. Can a mod sticky this and maybe rename to "a guide to backing up ffxi" or something?