Hack Into Mac Mini G4 Password

I got a second-hand mac G3 for Christmas, from the sysadmin at my dad's office. Unfortunately, the sysadmin neglected to remove his accounts (and passwords), so as of yet it's impossible to get past the boot screen. Does anyone have any ideas about how I may crack the password or hack into the account... (changing the root password in single user mode doesn't work...) Oh, and by the way, it's running OS X of some sort, but since we can't log in, it's hard to know what cat it is.
Help please!
UPDATE:
With the help of this site, we made an administrator account. We still don't know the master password, and there are a few untouchable files, but we can basically do whatever we want. The next challenge is to connect it to the internet...
If you want to know how we got in, here's what we did:
(1) we held down command (the propeller) and S as it booted --> this opened single-user mode, a command-line interface with root priveleges
(2) instead of 'rm'ing (removing), like the web site suggested, we 'mv'ed (moved) /var/db/.AppleSetupDone to /var/db/.AppleSetupDone.old
(3) we rebooted, and followed the instructions on the screen
What did this do? It moved the file that told the computer that the computer was set up, so the computer ran the setup 'wizard' like it was the first time the computer had ever been booted. After that, all we had to do was follow the instructions on the screen to set up an administrator (root) account.
We also learned that the cat is panther, so we might be updating it to a newer version.
Thanks for the help!

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Hack Into Mac Mini G4 Password Download

If the password hint doesn't show up, that will be because it wasn't set to show password hints in the Login Options. Unfortunately, the only way to change this setting is to log into your Mac.