@SlmJon
Found it. I'm sorry but I'm not familiar with a Dell computer. They are different from other computers.
Here is the website:
http://www.hiren.info/pages/bios-boot-cdrom
Use the F2 key and change the sequence. Maybe you should try to disable the hdd from the sequence as long as we are trying to fix the computer. The first boot device should be the CD/DVD drive.