http://home.eunet.no/~pnordahl/ntpasswd
Try using this! Works like a charm and works on 98/2000/xp... I know, tried them all.
Best thing, reset the password and when it asks you for a new password (the script), type *, this will blank out the password.
I downloaded the ISO and burned it to a cd, then rebooted the PC using the cd i burned and it automaticaly starts the script, simple yes/no stuff.
Check it out!