HOW TO: Enable or Disable the CTRL+ALT+DELETE Sequence for Logon

This describes how to enable or disable the CTRL+ALT+DELETE sequence for logging on in Windows XP.

You can require users to press CTRL+ALT+DELETE before logging on to a Windows XP-based computer, or you can eliminate this requirement for a faster logon process. Note that you must be logged on with Administrator rights to perform this task.

To Enable or Disable the CTRL+ALT+DELETE Sequence

1. Click Start, click Control Panel, and then click User Accounts.
2. Click the Advanced tab.
3. In the "Secure logon" section, select or clear the "Require users to press Ctrl+Alt+Delete" check box.

Troubleshooting

- Disabling the CTRL+ALT+DELETE sequence creates a "security hole." The CTRL+ALT+DELETE sequence can be read
   only by Windows, ensuring that the information in the ensuing logon dialog box can be read only by Windows. This can
   prevent rogue programs from gaining access to the computer.

- If a Windows XP-based computer is part of a domain, domain-wide policies may have been set that override the settings
   you make on the local computer.

- On MS-DOS-based computers (and some older UNIX-based systems), pressing CTRL+ALT+DELETE gains the
   attention of the BIOS, causing a "warm" reboot. You can use the keyboard to shut down the operating system. On
   Windows-based computers (starting with Microsoft Windows NT), the CTRL+ALT+DELETE sequence is intercepted by
   Windows. The advantage of the keystroke-intercept technique is to help prevent Windows from being shut down by
   someone who does not have access to do so.

Lock Your Computer and Use Other Windows Logo Shortcut Keys

This describes how to quickly lock your computer as well as the other Windows logo shortcut keys that you can use.

Windows XP includes a new Microsoft Natural Keyboard shortcut to lock your computer. Any other compatible keyboard that includes the Windows logo key and the Application key can also perform this task.

To use this shortcut, press the Windows logo key+L. The following list has different computer lock-up scenarios that are available to you, as well as other ways to lock the computer:

Fast User Switching Enabled

If the Fast User Switching feature is enabled and you lock the computer, you can observe the same behavior as if you switched users: The computer returns to the Welcome screen and other users can log on to the computer.

Fast User Switching Disabled

If the Fast User Switching feature is disabled and you lock the computer, the Unlock Computer dialog box is displayed that requires the current logged-on user to enter a password to unlock the computer.

Welcome Screen Enabled

If the Welcome screen is enabled, the computer can also be locked if you press CTRL+ALT+DELETE (to open Task Manager), and then click Lock Computer or click Switch User on the Shut Down menu.

NOTE: The ability to observe "Lock Computer" or "Switch User" on the Shut Down menu is dependent upon whether or not the Fast User Switching feature is enabled.

Welcome Screen Disabled

If the Welcome screen is disabled, you can lock the computer if you press CTRL+ALT+DELETE, and then click Lock Computer in the Windows Security dialog box.

In all of the preceding scenarios, the "Windows logo key+L" shortcut can lock the computer. If you do not have a password that is set for your user account, anyone can unlock your computer. To set a password for your user account: In
Control Panel, double-click User accounts, select your user account, and then click "Create a password".

Pressing CTRL+ALT+DEL & Cancel Appears to Disconnect Session

While you are using Terminal Services Advanced Client in Full-Screen mode, if you use the CTRL+ALT+DELETE key combination to lock the session, and then you click Cancel, this appears to disconnect the Terminal Services session.

This problem is caused by the behavior of Terminal Services Advanced Client, which is an ActiveX control. The control becomes independent of the Microsoft Internet Explorer shell during full-screen activation. In some scenarios (such as ALT+TAB, CTRL+ALT+DELETE, or in a multiple-monitor environment), if you switch to the Internet Explorer window that is hosting the control, it appears to host a blank control.

To resolve this problem, you can restore the session by clicking the Full-Screen icon at the bottom of the screen, or press ALT+TAB to switch back to the Terminal Services session. When you press ALT+TAB, you can switch between active programs.

Here is sample scenario of when this problem may occur:

1. Start a Terminal Services Advanced Client session.
2. Press CTRL+ALT+BREAK to put the session in Full-Screen mode.
3. Press CTRL+ALT+END to lock the session.
4. Press CTRL+ALT+DELETE.
5. Click Cancel.
6. The Internet Explorer page appears blank.
7. The session appears to be disconnected.

In this scenario, the session is not actually lost. You can restore it by using the methods described in the "Resolution" section in this article.

Administrator Unable to Unlock a "Locked" Computer

After you restart a computer running Windows and no one has logged on, you may be unable to log on to the computer either locally or to the domain.

The following error message may be displayed at logon:

This computer is in use and has been locked. Only or an administrator can unlock this computer. Press Ctrl + Alt + Del to unlock this computer.

If you try to unlock the computer, the following error message may be displayed:

This computer is locked. Only or an administrator can unlock this computer.

If a user has logged on and logged off, you may be unable to log on to the computer (locally or to the domain) and the following error message may be displayed:

This computer is in use and has been locked. Only <domain>\<username> or an administrator can unlock this
computer. Press Ctrl + Alt + Del to unlock this computer.

If you try to unlock the computer, the following error message may be displayed:

This computer is locked. Only <domain>\<username> or an administrator can unlock this computer.

NOTE: In the error messages above, <domain> is the domain name of the last user who logged on to the server and <username> is the name of the user who last logged on to the server.

This behavior can occur for either of the following reasons: When the default screen saver is set to use a non-existent screen saver program.  When you use a corrupted screen saver that is password protected.

To resolve this problem, use another screen saver program (such as Logon.scr) that is installed locally on the system or that is not corrupted.

1. Start Registry Editor (Regedt32.exe).
2. Locate the Scrnsave.exe value under the following registry key:

                 HKEY_USERS\.Default\Control Panel\Desktop

3. On the Edit menu, click String, type "logon.scr" (without the quotation marks), and then click OK.
4. Locate the ScreenSaverIsSecure value.
5. On the Edit menu, click String, type "0" (without the quotation marks), and then click OK.
6. Quit Registry Editor.

WORKAROUND

To work around this problem, use the appropriate method.

Method 1: When the Error Message States the Computer Is Locked by <domain>\<username>

1. Press CTRL+ALT+DELETE to unlock the computer.
2. Type the logon information for the last logged on user, and then click OK.
3. When the Unlock Computer dialog box disappears, press CTRL+ALT+DELETE and log on normally.

Method 2: When the Error Message Does Not State Who Locked the Computer

1. Use the Shutdown tool in the Microsoft Windows Resource Kit and attempt to shut down the locked computer. The
    System Shutdown dialog box is displayed on the locked computer, but the computer does not restart.
2. When the shutdown timer expires, the "Welcome to Windows" dialog box is displayed.
3. Before the screen saver becomes active, press CTRL+ALT+DELETE, and log on normally.

NOTE: If you do not use one of these methods to log on, you must restart the computer and log on before the screen saver program starts.

MORE INFORMATION

For additional information, click the article number below to view the article in the Microsoft Knowledge Base:

Q99590 How to Activate the Screen Saver During Logon

Q229687 Err Msg: 'Workstation Is Locked' with Invalid Screen Saver

HOW TO: Change the Logon Window and the Shutdown Preferences

HOW TO: Use the Fast User Switching Feature

HOW TO: Change the Windows Logon Screen Saver

How to Change a Computer Name or Join a Domain in Windows XP

XP Support- 01/01/2005 12:42 AM - Home Page WinXP
© Copyright Kelly Theriot MS-MVP(DTS) 2005. All rights reserved.