A next natural step would be to try booting from either the Network or from a USB flash drive. That will help isolate whether the problem really is isolated to the CD drive or not.

Google 'netbootin' to get a handy utility for taking almost any LiveCD image and making a bootable USB stick out of it. I am running a Knoppix LiveCD on the USB stick right now, made using netbootin.

Of course, you will have to run this on another machine: you can either use an ISO image you have downloaded separately (as I did) or connect directly to certain distributions and download the latest from their repository.