Hello, yesterday I have bought this one, and have a randomly off problem. Is that problem with powerbutton-sensor or monitor firmware?

Drivers & DDM are installed.

OS: Windows 8.1

Videocard: MSI N460GTX Cyclone 1GD5/OC: 2 DVI, 1 mini-HDMI

Intel HD4600 - same result

Link: Telecom cable, DVI-D to HDMI.

Monitor is very good but what should I do?