*I just bought a Asus ROG GR8 desktop and a Asus VG248qe screen. The desktop is powered and plugged to the screen with a HDMI cable, but the signal just says dvi no signal and then turns black. How this can be solved?*
if you have a local computer store or best buys try a dvi to hdmi cable or another hdmi cable. if the cable not right it can block the monitor from turning on. also in the monitor see if it set to turn on from the hdmi port first and not dvi port.