It's possible to install Medieval: Total War/Viking Invasion a second time.
But you can't use the install routine that's on the CD, that gives you an error telling you that you already have it installed.
What you have to do to get a second install is actually much simpler (You just need your Windows Explorer and your mouse):
  1. Find the main "Medieval - Total War" folder on your harddisk. (default path is "C:\Programs\Medieval - Total")
  2. Right click on the main folder and select "copy"
  3. Right click in the parent directory ("C:\Programs\" in this example) and select "Paste" (Insert). Your PC will now make a new folder called "Copy of Medieval - Total War" in the directory C:\Programs\
  4. Your "Programs" folder now contains two versions of Medieval: "C:\Programs\Medieval - Total War" and "C:\Programs\Copy of Medieval - Total War"
  5. You may now rename the "copy of" to "Samurai Warlords" by right clicking the folder and changing the properties/ the name. (not required but looks better)
  6. As a last step you find the Medieval.exe file in your new folder "copy of...." and with the right mouse button drag it to the desktop and drop it there. From the menu that pops up when doing so, select "Create Shortcut".

  7. You now have a second copy of Medieval and a shortcut to it on your desktop.
    BTW. This works for all mods of Medieval:Total War

For questions concerning this site: mail to R'as al Ghul