Changin display\Resolution using Visual C++

I am making an application to save me a bunch of time. One of the things I need my application to do is be able to change the display from 16bit to 24bit. If anyone can help my (give me the code) it would be greatly appreciated. Thanks Also how do I run programs that are not in the Windows directory? Thanks You know your game is in trouble when the lead designer of your racing game drives a mini-van.