Monitor turn off after long period time

Why does my screen sometimes goes blank after a period of inactivity ( like 8 hours )? And sometimes not!. My monitor screen just turns off ( yellow light ). Then i just turn my mouse and screen goes back to normal. ITS TOTALLY RANDOM!


I have disabled all sleep functions.
I disabled the screen saver and I disabled the OPTION of the OS turning off the screen. Yet, the screen will still turn itself off after a period of inactivity. I'm currently using a BENQ G2250. All power saving is disabled in monitor menu.
Due to inactivity my monitor can shut off after 13 hours , but sometimes he dont shut off after for example 14 hours.





PC:
4790K
8gb ram
Asus Sabertooth Z97 Mark 2
Corsair 750 RM
Asus Strix 980 Ti
monitor: BENQ G2250

Hi and welcome to SevenForums,
Nice build especially the asus 980TI I was looking at that the other day :)
You might confirm the screen mode your using ?

Senseye® 3 Visual Solution to Your Everyday Viewing Needs Experience the truest colors of the world with the BenQ Senseye® Human Vision Technology. With the help of its six proprietary calibration techniques, Senseye® 3 delivers only the best viewing quality in each of its six pre-set viewing modes –Standard, Movie, Game, Photo, sRGB, and Eco – with the Eco Mode especially designed to save power and money.

Could be corrupt power plan restore to default and redo it if you haven't already and or make a new power plan and theme.