I agree with roy It 69. When the screen is flashing try all the "F" numbers. In my experience it is usually F2 or F12. I use Ubuntu 12.04 on a very old machine and I can get to "recovery mode" at F12. There is a menu with options that doesn't require a password. I think the BIOS is F2, but I haven't tried it in a long time.
You might consider using this Ubuntu release. One problem arises, my machine won't accept the Desktop CD and I have to use the Alternative CD. Good Luck.