I am using OSX Panther 10.3.9.
I bought an iBook Clamshell Indigo and only got it running the other day. Turns out the previous owner "Ryan" has left his password on it and I am restricted to what I can do.

Luckily he has turned on automatic login so I can still use the account, but I want my own password so I can turn the automatic login off.

I do not have a Panther CD. I don't want to have to buy one. I am considering putting Xubuntu on it in the future but for the time being need to have my own password.

I tried a hack by pressing command S on startup and typing in what it told me to (something about mounting and passwd commands) but it didn't work.
No worries. The owner didn't lock the system preferences, so I was able to make a new account, give it administrator privileges, login to the new account, and delete the old one.