You can reset the system password if you still have the ibook original install disk or with a retail installation disk. Just boot the ibook with the installation disk holding the C key when you ear the chime until you see the grey screen with the apple. Once the system disk is loaded, choose a language and on the next screen go to the Utilities menu and choose the Reset Password sub menu, write the new password for the ibook volume and that's it. Exit the installation procedure and restart choosing your ibook HD.