Re:More Pictures (Score 1)

They use control-Alt-Delete because if you have noticed that brings up the Windows task manager or the logon screen. It is a security feature because at one time a good programmer could write a program that looked like a logon screen and when the user typed in his password then the program could capture the password. With the control-alt-delete feature then instead of bringing up a login screen a task manager will now show.

Besides if it bothers you, you can disable it from the group policy editer