Will not allow boot from cd

Dell Dimension 3000 will not let me boot from the cd drive. It does not give me the option  for cd rom when i push F12 to select a boot device, and when i enter setup to change the boot order it sees the drive but says not installed next to it. I have swaped out the IDE ribbon and even threw in a known working test rom drive and nothing changes. Does anybody know of a solution?