Well if you used add features in windows 8.1, you should be able to remove it the same way remove the Pro Product key and your computer will hide the pro features. If you clean installed the pro version then most likely you deleted the recovery partition and there would be no way to put the factory image back on. If you clean installed Pro the you'll only need to clean install windows 8.1 Core you can get your ISO
here Get you hardware drivers here
Asus Support Download You will get more responses if you post in the correct forum
http://rog.asus.com/forum/forumdisplay.php?198-G751-G771-G551-and-GL552-Gaming-Notebooks.
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