I have tryied to boot from the CD sent by the company on a dell inspiron 6400 and I got some errors. I guess it was the graphical interface that was not recognized. the laptop is prety new intel core duo, I do not know more details, but it should have been working :(
Ubuntu 7.04 on dell inspiron 6400
Archived thread 467809 from Dell Ubuntu Support. Markdown source: Dell__Ubuntu_Support/thread_467809_Ubuntu_7.04_on_dell_inspiron_6400.md
Would be really handy if you could tell us the errors so that we can troubleshoot them :)
(you may want to try choosing the "safe graphics mode" as opposed to "start or install ubuntu" when you get the choice at boot.