Regarding Windows 2003

Hi,
I have installed windows 2003 with active directory.I have a problem,I forgot the my administrator password and I also don’t have any other administrator and it is not possible to install the Windows 2003 again because of lots of data.
So I would apprecicate if someone provides me the assistance on it.
Is there any free tool or any free utility which resets the windows 2003 administrator password.

Regards.

Anurag.