This has happened with 2 different DVDs. One from the Linux Bible and One from Knoppix hacks. It works great the first time, but any boot after that is cannot find the DVD/CD player. I can see it searching, their is a rolling file sda, sda2, hda,etc. then a "Knoppix cannot find filesystem" shows up...I've tried it on different computers and both disc do the same thing. This are not downloads these are disk that came with the book? Any help will be greately appreciated. I already tried BIOS, as one person in this forum suggested as it worked for them, but did not work for me..