Disable the BUILTIN Administrator account in Windows

• 1 Don't rename it.
  
• 2 run cmd.exe with admin rights
  
• 3 net user administrator /active:no
  
• N Make sure you have another administrator account before deactivating!
  

References

• http://serverfault.com/questions/180156/in-windows-2008-should-i-rename-the-administrator-account-or-disable-it
• http://technet.microsoft.com/en-us/library/cc766343(v=ws.10).aspx
• http://serverfault.com/questions/301950/whould-changing-the-administrator-username-effect-the-other-setting-on-my-window