Ctrl-Alt-Del disable in NT4

I have developed software that requires Ctrl-Alt-Del to be disabled, this works fine for Win95/98 but not for NT4.

I need a piece of code that lets me disable the Use of Ctrl-Alt-Del (which normally opens a message style box with blank background and options like Lock, Log off, Change Password etc), and instead allows me to use the Keypreview method to let me do whatever I want to do when a user uses Ctrl-Alt-Del .

I suspect that this may not be possible for security reasons but I would like to do this to change what access to the system employees have, without changes permissions.