Leopard Extreme no boot from CD/DVD

[mcpetersen.dsm]

I have a year-old Leopard Extreme (leox2) running Ubuntu 12.04. I am unable to get it to boot from a live CD/DVD. Following the on-screen directions to press CTRL-M or spacebar, neither option does anything. Eventually there is a message to "press any key to boot from CD or DVD. No matter what key is pressed, the machine simply goes on to boot from the HD. Holding down F1, F2, F7, F10 or F12 does nothing.

How can I get this machine to boot a live CD/DVD?

[mcpetersen.dsm]

Problem solved. Using a different keyboard (Sony in this case) worked with the F10 key where the keyboard supplied with the computer (Logitech) did not.