If you can't see the dvd drive as a boot option, then bios don't know it is there.
First you have to check if the dvd drive is connected properly.
And then you have to enter bios, and load the defaults (usually F9).
Remember to save the changes in bios (push F10 to save and exit bios).
At the next boot, dvd drive should be an option on the boot list. :)