Dell XPS 600 - cannot reformat, or even boot from disc

Hello. i own a Dell XPS 600.
i loved it up until it started to malfunction. first, both the DVD-RW and the CD-RW would only be detected about every other boot up. I tried to reformat, but ended up just reinstalling windows.
However, this did nothing except mess things up further. i could see all of my old files on my computer, but could only boot into the new windows. this was annoying, and I called dell.
I eventually had to have a technition come to my house and replace my motherboard. i was excited that this fixed the DVD-RW and CD-RW error, however the reinstalling of windows left me with around 40gigs of unwanted data. I can see all of my old documents and such, but cannot do anything about them.
I then tried to reformat. that was terrible. I cannot delete the C:/ partition, and the partition that has that useful dell thing that reformats back to factory defaults is all messed up.
I believe my only option at this point is to completely reformat. everything has become very awkward, and I am running out of space.
however! and here is the real problem:
my XPS 600 will NOT boot from a cd, or dvd-rom.
i tried the Windows media media center 2005 dvd-rom (reinstalation cd)
i then tried a windows 98 cd (only copy of windows that I had on CD)
and then tried to boot up ubuntu, failure. then knoppix: failure.
it is like the XPS doesnt recognize the cd or dvds for bootup.
i tried searching online, and found someone with the same problem, but that was resolved, and what he did I tried and it failed.
anyway, my questions are: has anyone else not been able to boot from cd or dvd? is there a way to fix this? Message Edited by shammamishue on 12-21-2007 03:24 PM

Message Edited by shammamishue on 12-21-2007 03:27 PM