Quote Originally Posted by gabriele
I have not checked either of the two Knoppix CDs I tried to use on a different computer, but I did try to run two Windows XP Pro installation CDs on another computer after two failed attempts at running them on my computer, and they had been turned into coasters. Again, the installation CDs for Windows XP were perfectly legal (the license holder had burned them for me as part of their license agreement).

I'll try the Smart Boot Manager to boot Knoppix. I appreciate your help.
I guess that there could be a problem where a CD drive destroys writeable media if it somehow writes when it should read. Never heard of a real case of it though. You seem to have done some of the steps that would prove that something is happening to CD with your above tests, but hardly enough. I would burn CD's on a different system (or get some burnt CDs) and see if I could read them on the "different computer" above, then and only then try them in the suspect computer. Then, if the suspect computer fails, see if they can still be read in the "different computer" or if they are now bad. And if bad a tool like ISOBUSTER might give you some insight on what is now wrong with the CD. Of course, I would look at the CD closely to be sure it wasn't becoming extremely scratched, but I would expect you have already done that.

There is also a chance that you are writing the CD too fast; I always recommend 4x or as slow as the drive will go (a few new drives seem to burn no slower than 8x). Higher burn speeds do cause problems. See http://www.knoppix.net/forum/viewtopic.php?t=17788
and
http://www.knoppix.net/forum/viewtop...?p=78925#78925
for examples, search the forums for the words burn and speed for many more. And, of course, try SBM. You might not even need it once you resolve the other issues, but it will not hurn and will avoid any BIOS CD boot problems.