Easiest way is to boot up from the machine (don't use Knoppix) and when you get to the Lilo prompt (press Esc if you have a graphical display), type "linux single" or "linux 1" at the prompt and then press enter - this takes you to Single User Mode, which gives you root access. Then at the prompt, type "passwd root" (no quotes), and it'll ask you to type in a password, which will be your new one, and then it'll ask again to make sure you did it right. Bingo!