Unable to login to server after resetting password

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http://serverfault.com – in my Windows Server 2003 server, I have 2 administrator account (let's call them admin1 and admin2). I logged in as admin2 to reset admin1's password but I'm not able to login after that. I have checked and verified that the admin1's "Account is disabled" option is not checked. However, the "User cannot change password" option is enabled. Is that preventing me from changing password on admin1 account? Thanks. (HowTos)