From the top, please.

[JackUser]

Can't get anything but Windows to boot: Downloaded the ISO (4.0.2). At first, I understood to burn ISO image to a CD--wrong. Next burned the contents of the ISO (autorun.bat, index.html, boot directory, knoppix directory, etc...numerous files) to CD with Roxio. Burned at 4X, verified. Set BIOS to boot CD-ROM before HD. Restart. Windows (XP Home) comes on. Tried on 2 different PCs, one with XP Home, one XP Pro. Windows loads. If I click on CD icon, it launches the default browser and displays the Knoppix welcome screen, so the CD is readable to that extent. Have I misunderstood what "burn image to CD" means? What should the contents of the final burned CD look like? What file is it looking for to boot? It must be there...but it won't load.

[Harry Kuhman]

.... burn ISO image to a CD--wrong. Next burned the contents of the ISO (autorun.bat, index.html, boot directory, knoppix directory, etc...numerous files) to CD with Roxio....
Wrong again. You don't extract anything from the ISO. Read the Downloading FAQ, it's pretty well covered there.