If the firmware is UEFI and the disks in the bios are set to raid or ahci, efi booting will be enabled. To clean the dis, boot the windows installation media, once in press shift and F10 and you'll get a command prompt. In there do diskpart, then list disk, then select disk 0 or whatever disk it is and then do clean. It'll wipe all partions from the drive. Then exit out and reboot the machine back to the installer and install windows. It'll create the partitions it needs for you.
Hope this helps
Rich