This notice applies to all potentially BenQ HDMI monitors, but certainly for the GL2450HM. Anyone who wants to connect the monitor via HDMI, it first needs to connect to the computer via D-SUB / VGA. Only then (!) Opens the Monitor's menu and adjust as desired there HDMI interface. Who has no VGA port, HDMI or DVI only (eg DVD player), receives from the monitor mercilessly the message: "No cable connected". And when no input signal can be, as I said, do not open the Monitor menu. Even if you did not know that BenQ, which is why my first monitor as "defective" again went back to Amazon.
By the way, who is running on a Windows 7 system monitor with an ATI graphics card and is surprised at full resolution over black borders on all sides, which open the Catalyst Control Center ("extended"), click the menu item "Graphics" - "desktops & Display "Right click on the screen, then select" Configure "and put in" scaling options "the slider to zero. Only the great programmers know why it checks its users with a different scaling default.
Otherwise the monitor in the other reviews everything has been said: price / performance value.