Stupid Linux or Stupid iMac

I have been trying to get this imac to boot from a cd for a while now and it keeps hating me. I put in the cd, push the power button, hold down ‘c’ and all it does is flash the folder ‘?’ nonsense and then loads the normal OS. Why?

So I thought maybe I had made my disk wrong. So I re burned another copy, no luck. I am now downloading Damn Small Linux to try that tonight. Stupid iMac.