Windows cannot be installed on this disk. Windows can only installed on GPT disks.

Windows cannot be installed on this disk. The selected disk has an MBR partition table. On EFI systems, Windows can only installed on GPT disks.

The actual correct way to install 8.1 is on GPT.

At the partition screen of windows setup hold down Shift+F10

Type the following -

diskpart (this will take 3-10 seconds to load)

DISKPART>select disk 0
DISKPART>clean
DISKPART>convert gpt
DISKPART>exit

X:\System32>exit

That will take you back to the partition screen of windows setup, then click refresh and then click Next.