As I suspected, the keys aren't registering to allow you to boot from a CD or switch the startup disk. I am going to assume that you wont be able to reset the pram or do an SMC reset either. You can try anyway...
PRAM reset
hold Option + Command + P + R and press the power button. Hold those keys until you hear the startup chime at least 2 times.
SMC Reset
Shut down the computer.
Plug in the MagSafe power adapter to a power source, connecting it to the Mac if its not already connected.
On the built-in keyboard, press the (left side) Shift-Control-Option keys and the power button at the same time.
Release all the keys and the power button at the same time.
Press the power button to turn on the computer.
Safe boot
Hold the shift key whilst rebooting.
You can try these three things, but I'm leaning towards a hardware failure on this as it seems the KB is not functioning even prior to the OS loading.