That cable you are using is better known as a VGA cable and designed for older analog inputs. BenQ can use it, but it will be not very good for gaming unless you tie it to a DVI adapter at the video card, if that video card offers DVI. (I run a pair of 24" BenQ gaming monitors and they work great for me that way on my Mac Pro Tower's Nvidia GeForce video card.) Note that there is an on screen menu that should be described in your monitor owner's manual (available at BenQ as well) that allows you to select the monitor connection type. You might check it to be sure it is set correctly.
If it happens to be one of the standard Cyberpower computer models, the video card is sideways (parallel with the bottom of the computer) and about 1/2 way up the back of the case. The video you are using is the motherboard default video with the VGA cable turned sideways (so that it is positioned with a screw at the top and the other at the bottom) and connected near the top of the case rear. You could play in the bios and connect it, but it will give slow video frame rates.
You need to look at the video connector(s) on the video card and compare them to http://support.benq.us/customer/portal/a… Then get a cable for one of those that will also connect to your monitor.
My BenQs have HDMI and VGA ports, but there are adapters for DVI to VGA as well that would allow using your VGA cable for the monitor connection and the adapter to the computer's video card if your video card uses DVI instead. That will be a much faster video feed than straight VGA, because it will be using the much faster processor and larger VRAM on the video card. If you have HDMI, it is an even faster video feed. Your computer probably has the video feed from the video card set as the default video and this is one place where Windows is NOT plug and play.
a sub D cable??
you need a HDMI, DVI (or DVI-D) or a VGA cable, a Sub D cable is not going to work, it's probably what the issue is.
if you have the name of the cable mixed up and are using the correct cable, make sure it's connected to the graphics card and not the onboard graphics (or it might need to be switched to the onboard graphics and changed in the bios to the graphics card).
the onboard graphics will be at the top/middle of the case on the back, near the USB slots, the graphics card will be at the bottom of the case.
Please provide a good picture of the BACK of the PC.
Just a guess… I'd say that your new PC has an HDMI or DVI video card, and that Sub-D port is legacy VGA, and not active. You need to find the active video port, and use the right cable.
Joe might be right, but with no part numbers or picture of the back of computer, we are just blindly guessing.
You did it wrong