The UEFI Boot sequence doesn't take too kindly to optical drives. It is better to make a bootable USB using Rufus:

http://rufus.akeo.ie/

See here for an example:

http://dellwindowsreinstallationguide.com/converting-your-dell-windows-reinstallation-dvd-into-a-reinstallation-usb/

If making recovery media using the latest version of Alienware Respawn ensure that you use USB media (USB flash drive or USB external hard drive) and not a DVD:

http://dellwindowsreinstallationguide.com/dell-backup-and-recovery-1-8-1-71/