Tried lots of things ... but won't boot

[Loper]

I used Easy-CD Creator from Roxio, with the option 'Disk-at-Once'.

...but the other issue is: did you burn it correctly, as an image -- not data? Look at the disk under Windows. There should be a directory on it called Knoppix, among other things. If all that shows is a single 700MB file, then you burned it incorrectly.

There is an option with CD Creator labeled something like "burn image"; I don't remember, exactly, since I have not used that bloatware for about 2 years -- but if you burn the disc as data, it won't work, except as a backup of the ISO image itself.