Help with reseting a pword on a Macintosh IBOOK g4?

There are two users on this computer, I am the Administrator on it, and I have forgotten my pword, I cannot go to the other user's site, and change my pword, I have also forgotten the Master Pword, and the Keychain pword. If you have any idea's on how i can change these without reseting the entire computer, and losing all of the information I would be much obliged!