>> Is there any API routine that would change the IP address of a Windows 9X/NT machine?
>If there is one you may have to reboot the computer everytime you do it!!

I would think that having a program to change your IP address would be an exceptionally BAD thing, especially for your network administrator.

What use would you have for doing this in a program, rather than through the native win9x/NT interface? (or through a network remote command center)