Password Recovery

I have two NT4.0 Domain. I have Windows 2000 Professional installed on my PC and I was connected to Domain1. I have changed my Domain to Domain2 but I am not able to logon to this Domain. Now even I cant login locally to put back my Domain as Domain1 because I dont know the administrator password to logon locally nad even we cant change the Domain in Logon menu. Will anybody can explain me is there any way to change the domain name during logon or is there anyway to logon locally without knowing the password ?