Windows Loader 2.1.5 by Daz is a software tool designed to activate Windows XP, Windows Vista, Windows 7, and Windows 8 operating systems. It works by exploiting a vulnerability in the WAT, allowing users to activate their Windows installation without a valid product key.
Your drive likely uses GPT/UEFI. The loader only works on MBR partitions. Windows Loader 2.1.5 by Daz WAT Fix