The password had change and nobody is responsible, so I did this:
1. I used a password reset cd and reset the administrator in the SAM (remember is a domain controller and use AD).
2. I restarted the server and press F8 and choose Directory Services Restore Mode (domain controller only).
3. Follow the instructions in this site:
http://www.petri.co.il/reset_domain_admin_password_in_windows_server_2003_ad.htmI tried first in a virtual machine and worked so I did live. In the beginning I tried to obtain the hash to crack the password, but I could not do it. I took me 5 hours but it worked.