I'm trying to run ubuntu 12.10 alongside windows 7, so that if one os crashes I have a backup. My machine is 64 bit intel celeron, i think 900ghz. Whenever I selected "install ubuntu" from the dvd options at startup and got to the page where it said "run alongside windows" and "replace windows." Whenever I select "run alongside windows," the screen flashes black, shows the ubuntu starting up/shutting down screen, and the progress bar does not move. After a couple minutes of not doing anything, the disk ejects. What exactly is happening to cause this?
-Many thanks in advance!

