Q I have tried all I can to get a Debian and Fedora dual-booting DVD working. But all my efforts proved abortive. The Smart Manager Bootloader could boot any other CD but not my ISO CD. Could you tell me anything else I can do to boot the CD? There is nothing wrong with the disc itself, the problem is with the BIOS of my machine that is not recognising the ISO on the CD.
A I assume you mean Smart Boot Manager for Smart Manager Bootloader. Your mention of ISO and CD leads me to believe that you have created CD ISO images for the DVD, using mkiso or winmkiso, and written them to CD-Rs. Especially as you also mention Fedora, which wasn't on the CDs. The usual cause of this problem is the way you write the ISO to the disc. If you copy it as a file, the disc will not boot. Look at the contents of one of the discs. If all you see is the single ISO file, you have copied the file instead of using it as an image. You should see a lot of files on each disc. This is because each ISO file is a complete image of the contents of the CD, all the files plus the booting information, so it needs to be copied to the disc in a different way.
In K3b, select Tools > Burn CD Image, pick the image file and click Start. If you want to burn the images in Windows, Nero is probably the best choice. Go to File > Burn Image from the menu and select the ISO image file in the dialog. When the Write CD dialog opens, go to the Burn tab and select Write then Finalise. Press the Write button to create the CD.
To use Easy CD Creator, select File > Record CD From CD Image from the menu. When the file dialog opens, set the Files Of Type drop-down to ISO Image Files. Select the ISO image you wish to burn and click Open. In the Record CD Setup window, choose Track-at-once and Finalise CD. Click OK to create the CD. You can find more information on using (and obtaining) ISO images on the LinuxISO.org website. The most relevant information is at www.linuxiso.org/viewdoc.php/howtoburn.html and www.linuxiso.org/viewdoc.php/isofaq.html.