I've downloaded the Knoppix 3.4 iso file twice (from two different mirrors) on two different machines and have verified both image files with the MD5SUM file. I've burned both images to a CD using Nero 5 and Nero 6 (yes, as an image, not as a data CD). I've tried booting both CDs on both CD-ROMs of both computers (8 combinations). I've triple checked the boot order for the CD-ROM first and the hard drive second on both machines. I'm up for any suggestions at this point.....thanks in advance for any reply.