Auto logon in Windows XP

Enable Auto logon

Go to Start>Run and type "control userpasswords2"
then select the user you want for auto logon.

Disable AutoLogon
Bypass Auto Logon at startup
By default, MSGina.dll checks the state of the SHIFT key when AutoAdminLogon is 1. If the SHIFT key is held down during the boot process, MSGina.dll will ignore the AutoAdminLogon key value and prompt the user for identification and authentication information interactively. You can use this method to temporarily disable automatic logon at startup.

Easy method to clear Auto Logon entry
Go to Start>Run and type "rundll32 netplwiz.dll,ClearAutoLogon"

Registry Method
Use this method only if you've configured the automatic logon using the registry manually. Because, automatic logon procedure using Control Userpasswords2 or using Tweak UI does not involve Winlogon \ DefaultPassword key at all. They are stored in protected area rather.

• Open Registry Editor (Regedit.exe) and navigate to:

HKEY_LOCAL_MACHINE \ Software \ Microsoft \ WindowsNT \ CurrentVersion \ Winlogon

• Delete the DefaultPassword entry.

• Double-click AutoAdminLogon, type 0 in the Value Data box, and then click OK.