Unknown password

I have an iBook with OS 10.1 installed and do not know the original password. I haven't needed it until now when I want to install OS 10.3. It won't allow the install without the password. I have no way of knowing or getting the password. I have the original disks that came with the iBook. I tried to re-install original OS 10.1 again hoping it would ask me for a new password but it did not. What next?
Thanks....noahsmom

You will need to boot your system from the OS X install disk. Insert the install disk, reboot your system. Press and hold down the C key, until your system starts. Once you have the install menu up on the screen. Look under the drop down menu. You see an option to reset the system pass word.