First off read this
sticky thread, it explains and has guides for downgrading to windows 7, a couple of points you must us a ISO win7 SP1, must be SP1 to support UEFI GPT. The second point is to create your install media USB is best, to boot and install UEFI GPT. Your SSD should be Clean, as in no partitions no format. Clean, The issue your experiencing is most likely your SSD is BIOS MBR and your system is UEFI GPT, If you must set up your SSD set it up UEFI GPT.
One more important thing to do first before anything else download
backtracker and create a restore to factory condition disk set. Just incase at some time in the future you need or want to restore your notebook back to factory shipped conditon
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