Domain Admin Password Recovery

I have inherited a Win2000 Domain (Administrator in a coma for 2 months and only he knows password). I have used a local password reset and followed a method described at Petri.com and got into local admin, from where I ran msc DSA from dos prompt. Got into users and computers management, but the comatose admin has disabled local admin from changing domain users details and passwords. Is there a way I can reset the Domain Admin Password, or recover it – am at wits end and do not want to reload a new domain as it has 200 users in!