When an administrator removes or changes your password for local account,you no longer have access to your encrypted files and e-mail messages. That's because your master key,which is needed to unlock your personal encryption certificate is encrypted with a hash that includes your password. when the password changes,the master key is no longer accessible. To regain access to the master key and to your desired files,change your password to your old password. Alternatively, use your password reset disk to change your password.
When you change your own password(through user account or with password reset disk). windows use your old password to decrypt the master key and then re-encrypts it with the new password, so your encrypted files and e-mail msg. remain accessible.