Pressing Ctrl + Alt + Del in Windows 7 displays a list of options such as lock computer, switch user, log off, change password and start task manager. For some reason, you might want to disable one or two options, but unfortunately Windows doesn’t provide an easy way to do this. Advanced users can disable the options by tweaking registry, though.
Tweak CTRL + ALT + DEL is a free, portable utility that provides a user interface to directly disable/enable CTRL + ALT + DEL options. Mark off the options that you want to disable and click OK. When you press CTRL + ALT + DEL, the options are no longer displayed.