Remember that is is a PC and what drives control type people nuts is I can boot a KNOPPIX CD and look at and do whatever I want on most machines. What you can do to stop this and booting the PC is to set the BIOS PASSWORD.
But you pay dearly for this feature in that you pay people by the hour. Now you've increased the time it takes to boot the PC. Also, you pay them again to ask around for the boot password.
Maybe a better idea is to remove the games and only allow logons that have passwords?
A few of us use a computer with XP for office work. We want to set a password for using this machine that will keep other people from playing with it. Any ideas how this may be done?