It’s possible to auto login to Windows XP, and even force auto login to prevent a user from manually logging out from the system & logging in as another user. However, force auto login can be circumvented.

To enforce the policy so that Windows automatically logs back in again after any logoff, read auto login, & force auto login.

To bypass the automatic logon in order to let another user log in, hold down the SHIFT key while Windows XP is starting or after logging off.