I borrowed a friend's laptop (also Windows XP) and used the same Knoppix CD in his laptop as I did in mine and when I turned his on it booted into Knoppix without a hitch. I then ejected the very same CD, put it into my laptop and turned it on and nothing at all. Just the looping boot sequence as usual. I did hit Esc and it gave me four options, one of which was something about ATAPI CD-ROM. I selected that option and hit enter but all it did was bring me back to the Windows XP loading screen, which then in turn looped me back to the HP screen and so on...it wasn't any different than if I had done nothing at all. For good measure I tried the other 3 options it gave me after hitting the Esc key as well, but all to the same result. So the Knoppix CD itself works, I know that much...but getting it to work in my laptop is another story.