Enable Automatic Logon in WinXp

Click START >> RUN >> TYPE Regedit

Go to Registry Key:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon

Right Click on Value Name: DefaultUserName

Select Modify
Enter the account name to be automatically logged on in the Value Data Box ( Refer Screenshot Below )

Right Click on Value Name: DefaultPassword

Select Modify
Enter the account password in the Value Data Box ( Refer Screenshot Below )

Right Click on Value Name: AutoAdminLogon
Select Modify
Enter Values 0 = Disabled / 1 = Enabled in the Value Data Box ( Refer Screenshot Below )

NOTE :  If the above values are not present the same needs to be created

Click on Edit on Top.

Select New >> String Value >> Type the required Value Name