Dear Samantha - I think Dell has an issue in the OEM BIOS for Win 8 in its Optiplex line.  Despite all my efforts, I cannot boot from my CD-DVD drive even after I turn OFF Secure Boot and UEFI.  Then, yes, my machine DOES list my CD-DVD as a boot option, but when I actually try to boot from the CD-DVD, I get an error message.
(My new machine is an Optiplex 7010 Mini-Tower with Win 8 Pro 64-bit, 8 GB RAM, 500 GB hard drive and an Intel i5 3470 processor.  It has BIOS version A16.)

I have a detailed thread on this issue here:

Please take a look there for technical details and - I beg you - let me have your thoughts.  Only your OEM team will be able to fix this - please help!  Thanks.