Well since your drive won't read the Cd, you either didn't flash the bios correctly, have a DVD drive that doesn't read that particular media or brand of media, or you didn't make the ISO correctly.
Look through everything on here about flashing bios and making ISO's(I use Qxix but Craxtion is easy too).
What DVD drive do you have?
If we can get you to boot the Slayer's CD, you can FTP to your XBox and see if your Bios folder has the flashed bios in it. We have to get the C to work first though.