So If you have 8.1 Pro you should have gotten a Product Key with that? However to use you embedded key you will have to use a Window 8 core or OEM Disk or ISO. There are several embedded Key retrieval programs out there. Your Key is embedded on your motherboard not your hard drive.
Also you will have to boot your media UEFI As your original system came as UEFI GPT That was all explained in
Rewbens thread using Rufus is the best way to create your usb install media.
1) Download and extract the
Windows Product Key Viewer (you may skip step 1 & 2 if your laptop did not come pre-installed with Windows 8 and doesn't have a product key built into its BIOS)
2) Run pkeyui.exe by right clicking on it then choose Run As Administrator, then find your Windows 8 product key and write it down somewhere safe
http://www.eightforums.com/tutorials/18309-windows-8-windows-8-1-iso-download-create.html?filterhttp://www.eightforums.com/installation-setup/31093-activate-retail-windows-8-1-windows-8-product-ke...
G752VY-DH72 Win 10 Pro
512 GB M.2 Samsung 960 Pro
1 TB Samsung 850 pro 2.5 format
980m GTX 4 GB
32GB DDR 4 Standard RAM
Z97 PRO WiFi I7 4790K
Windows 10 Pro
Z97 -A
Windows 10 Pro