Hi,I have a Lenovo X200 Tablet machine running Windows XP professional. This issue doesn't happen *too* often, but enough times to be annoying.After 15 minutes of inactiviy, windows does the standard screen saver routine by locking the desktop. During this time, the white box that says Click control-alt-delete to enter in your password is visible. There is also the on-screen virtual keyboard.From time to time, i return to my computer to find out that the unlocking white box is missing!! There is no way for me to get back into windows!! I literally have to pull the battery out and reboot. During this time, I've lost all my unsaved data...not to mention I shut down not in the most graceful manner.Has this happened to anyone? What in the world could be causing this?Thanks for the feedback.

Hi Jim_B_NJ, 1. Have you set to prompt for password on resume on the computer? I would suggest that you run SFC scan on the computer which would scan for corrupt system files on the computer and replace them.The scan may take some time, so be patient. Windows will repair any corrupted or missing files that it finds. If information from the installation CD is needed to repair the problem, you may be prompted to insert your Windows XP installation disk.For more information refer the below link.Description of Windows XP and Windows Server 2003 System File Checker (Sfc.exe)http://support.microsoft.com/kb/310747 If you do not want windows to ask for password after resume try the below step to disable it.a) Right-click on a blank area on the desk topb) Select properties from the context menu that opensc) Left-click the screensaver tabd) Unclick the checkbox that says On resume, password protect to disable. e) Click OK If you do not want the Ctrl+Alt+Delete window on the logon screen try the below steps.a) Click Start, click Run, type Control Userpasswords2, and then press ENTER. Note You may receive the following dialog box:You must be a member of the Administrators group on this computer to open User Accounts. You are logged on as user name, and this account is not a member of the Administrators group.In this condition, you are required to type the user name and password when the system prompts the dialog box to type the user name and password of the administrator of the computer.b) Click the Advanced tab.c) In the Secure logon section, click to clear the Require users to press Ctrl+Alt+Delete check box if you want to disable the CTRL+ALT+DELETE sequence How to enable or disable the CTRL+ALT+DELETE sequence for logging on to Windows XP, to Windows Vista, and to Windows 7http://support.microsoft.com/kb/308226 Hope this helps!Halima S - Microsoft Support.Visit our Microsoft Answers Feedback Forum and let us know what you think.