Password to Windows200 Prof.

I changed the domain on my windows200 Professional computer which uses a VPN to connect to my Domain. However, when rebooted my password did not work. I do not remember my administrator password either.
Short of re-installing windows2000 prof on this system, does anyone have any ideas of how I can get into windows so that I may change back the domain to the previous one.
Booting to Safe mode, command prompt all require a password.