Ok. When you restart your rig, after the beep, start hitting the DEL key to get into the bios. Within the BIOS, go to Advanced BIOS Features. Looking down the list, find EFI CD/DVD Boot Option and make sure it is set to "Auto". Then, go down to Boot Priority. Set the DVD drive to be the first priority drive to boot from the CD. Hit F10 to save and exit. Then Windows should boot from the disc and you should be able to install on partition 3.