Problem with computers trying to automatically logon

Have rejoined 6 windows xp computers to an SBS 2008 domain using the http://connect wizard.  now every time the machine boots or reboots or a user logs out and goes to the logon screen, it tries to log on again but cant.  It says the user account is not found or incorrect password.  every time the machine tries to log on it uses the domain admin's username and local machine for 'log on to'.  this affects about 4 computers.  i tried dis-joining and rejoining one computer but still have problem.