How to hide any specific user account from windows XP welcome screen?

The windows XP welcome screen displays the list of all local users accounts except the built in administrator account, but if system administrator add a new user account for troubleshooting purpose and he wants windows XP does not display this user name at the welcome screen. So you can hide this user at the welcome screen using windows registry editor. 
 
Perform the following steps to hide the user at logon screen:

To edit this feature, you will need to be logged into your computer with administrative rights. 

First click on Start button to open "Run" and type "regedit" then press Ok button to open the Registry Editor. 

In registry editor locate the given path: 

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows 

First right click in the right side of the registry editor panel and create the new DWORD value then rename this key exactly as the username.

For example, you want to hide the username "tony" then DWORD value will be as:

Tony REG_DWORD

Double click on new DWORD value and set its value 0 under "Value data" section.

Close the Registry editor and restart your computer for changes to apply.  

Change this value 1 to display this user at welcome screen.  

To logon this hidden user account, simply press the CTRL+ALT+DELETE twice at the login screen then type username and password.