Pelikal,
Don't blame me if this causes you problems, but on OS X 10.3 it goes something like this ....
1/ Turn off computer
2/ Turn on whilst holding down apple and s
3/ Once it's all booted and you're on a black screen type /sbin/mount -uw /
4/ Type/sbin/SystemStarter
5/ Type passwd XXXXXX where XXXXX is the username of your admin account. Enter desired new password when prompted.
6/ Type reboot
If you don't know the username, before step 5, type :
nireport . /users name realname and use the value from the first column
Job done.
Last edited by mixture; 3rd January 2013 at 18:35.