Reset Domain Admin Password

I have a Windows 2000 Server, that is a domain controller using AD, where I renamed the administrator account and changed the password on the account. For months the account worked without problems, until a power-outage occured. Now, I am not able to log into the server with my password. How can I reset the domain adminstrator password, even if it has been renamed without having to spend a lot of money? I have tried the Linux boot disk, but that is only for local accounts. Thoughts?