Deleting and copying .dll files in MS-DOS or other

[BustaRomeo]

I want to take a .dll file from a game directory, and place it in the System32 folder. The .dll file already exists in the System32 folder, and is being used by windows/program, so I want to replace it with the .dll file I've copied from the game directory. How do I go about doing this entire process in MS-DOS? Or is there a program that I can use (in Windows XP) to perform this procedure? Please respond.