I appreciate all the cycles that have been put into getting clarification and giving comments.
Now that the what is known. This is the how that I have come up with.
I have written a program, actually modified one that I found. This displays on the full screen. In the middle of this screen is a password field. Entering the correct password closes the window and returns to the desktop. This works great.
Now, at or about midnight each computer will automatically create a new password, for that computer. This password will be encrypted using another routine that I found. The password will be stored in the registry. Although this has not been coded yet, the pieces that I have tried work great.
After the password is created it will be emailed to someone. In the morning this person will print out the emails. During the day this person will "sign in" people and give them the password for one of the machines. The person will use that password. I know that after each use a new password should be generated. However the person handing out the passwords has other responsibilities as well, and I do not want to add too much work. The mechanism for sending the emails work as well.
So, from the above, it seems that I have a complete solution. So what's my problem? Simply this. I cannot disable CAD, or Alt-esc, Alt-Tab or Ctrl-esc. Or can I? I would be quite happy to use my solution if I could disable these. Since I may not be able to disable these, I will have to determine whether that is a great concern.
If anyone can tell me how to disable some or all of these, I would be a very happy camper.
Thanks for the time spent
John