Hi Karen,
Don't try to open the files, the game will do that for you once you've renumbered and installed them.
You'll find the game folder in My Documents.
Save both files to your desktop (don't try to open them). Then make sure to renumber both files so that they will appear sequentially last in the game folder (they need to be the same number, as the 2 files make up one save). Then copy and paste both files across into the folder.
Exit the folder, start up your game as usual and load the new save - you will need to scroll down through the saves to find the new one.
