Would F12 display that option if CD is set to disabled in BIOS, Boot, section (F2)?

Check there, F2 at restart, Boot tab & see that CD is set to (not) disabled.

Note, F12 is for (manually) selecting, F2 is for setting.


Otherwise, https://www.google.com/search?rls=org.mozilla%3Aen-US%3Aunofficial&ie=UTF-8&oe=UTF-8&oq=&aqs=&q=dell+8930+boot+order+sequence.


PS: Computer have a CD/DVD ;-)