Disk Management cannot detect any Primary Drives

Hi all, My Disk Management detects my C: Drive as a Logical Drive instead of a Primary drive while EaseUS Partition Master detects it as a Primary drive. The problem now is that because it because Disk Manage detects it as a Logical Drive, I am not able to delete Free Space to change it into unallocated space to install dual boot Windows 8. (Triple, including Windows 7 and Ubuntu) Why...