I might have done something similar.
I have an old Dell Inspiron laptop that runs on Vista and XP
1. Went online and burned a copy of Ubuntu 12.10 to disk
2. Put in the disk and ran it.
3. When done, I had two operating systems to choose from at boot, Windows and Ubuntu.
4. I tested Ubuntu and it worked. Admittedly I did not test Vista to make sure still working.
5. Used terminal to tell Ubuntu OS manager to ditch Vista and XP.
6. Restarted computer, got message that there is no bootable device.
7. Got into BIOS settings, set up boot sequence to start with Cd drive
8. Tried to boot from Ubuntu cd again and this time failed
9. Took out an old Windows 7 disk that was originally for our Dell tower, tried that, and the Inspiron booted up!
What should I try next? I have no interest in returning windows to that particular machine - want it to be the Linux machine but I will if that is what it takes to get Ubuntu running again. Receovering data is not an issue here - all data backed up externally. Really just want Ubuntu running as nicely as possible, Windows or no Windows.