I have had to remove the hdd as a boot option before, but not even that is a guarantee. I asked if this was a Dell system as I have seen this occur before with them. The removal of the hdd from the boot list will work sometimes, and the rest of the time turn off quick boot so you can see the system options, and wait for the boot menu to come up. At that point, if the media is bootable, it should boot. A good test is to try and get your media to boot on some other system just for verification, or take a look at the disc to see if there is a boot area on it.
Let me know how far this gets you. After this you will need a robe, wand, and perhaps a hammer