Using CTRL+ALT+DEL key combination to open Windows Security opens Task Manager

On a Microsoft Windows XP-based computer that is not joined to a domain, when you use the keyboard combination CTRL+ALT+DEL to open the Windows Security window, Task Manager is opened instead.

This issue occurs if you configured Windows XP to use the Welcome screen.

To resolve this issue, disable the Welcome screen. To do this, follow these steps:

1. In Control Panel, click User Accounts.
2. Click Change the way users log on or off.
3. Click to clear Use the welcome screen for fast and easy logon.
4. Click OK.

Note The Fast User Switching option is disabled if the Welcome screen is disabled.

This behavior is by design.

Most of the options that are available on the Windows Security window, including the Locking the computer option, can be selected on the Shut Down menu in Task Manager. You can also lock the computer by using the Windows logo key+L keyboard combination.