It sounds like a bad cd burn. As AK Dave suggested, burn slow, no faster than 8X. Also burn in a RAW mode, usually listed as DAO. Be sure to burn it as an iso, not a data cd. Check and make sure your BIOS is set so the cd drive boots before the hard drive.
Insanity: Doing the same thing over and over and each time expecting a different result.
Democracy is 2 wolves and a lamb voting on the menu. Liberty is an armed lamb protesting the electoral outcome. A Republic negates the need for an armed protest.