Require Control+Alt+Delete For More Security in Windows XP.
For additional security, enable the
Control+Alt+Delete login screen for XP. Using this is far more
secure than the traditional XP login screen due to the fact that
no program can intercept CTRL+ALT+DEL. Thus you are protecting
yourself from a application (a bad application, could be spyware
or a virus) from learning your machine password.
Click

then

Type control userpasswords2 then click

Click on the Advanced Tab
then put a Check Mark in
the Secure Login section.
Then Click Apply and then
Reboot and the Control + Alt + Delete
screen should pop up.