https://support.microsoft.com/en-us/kb/324737To use Registry Editor to turn on automatic logon, follow these steps:Click Start, and then click Run.In the Open box, type Regedt32.exe, and then press Enter.Locate the following subkey in the registry:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
Double-click the DefaultUserName entry, type your user name, and then click OK.Double-click the DefaultPassword entry, type your password, and then click OK.
Note If the DefaultPassword value does not exist, it must be added. To add the value, follow these steps:
On the Edit menu, click New, and then point to String Value.Type DefaultPassword, and then press Enter.Double-click DefaultPassword.In the Edit String dialog, type your password and then click OK.
Note If no DefaultPassword string is specified, Windows automatically changes the value of the AutoAdminLogon key from 1 (true) to 0 (false), disabling the AutoAdminLogon feature.
On the Edit menu, click New, and then point to String Value.Type AutoAdminLogon, and then press Enter.Double-click AutoAdminLogon.In the Edit String dialog box, type 1 and then click OK.Exit Registry Editor.Click Start, click Shutdown, and then type a reason in the Comment text box.Click OK to turn off your computer.Restart your computer. You can now log on automatically.