Monitor Says No signal after factory reset

Hold the Power button for 6 seconds to ensure the computer is fully off.

Press the power button as normal to switch on.

Do you get the ASUS logo or the BIOS startup messages on the display before it then goes black and the message appears?

If not then you have a problem with the hardware. These are generated by the computer BEFORE control is passed to the hard disk and Windows starts to load.

The other possibility is the video output is actually going to another port. Graphics cards should scan all ports to see if a monitor is connected and either output to all connected screens or define one as the primary. In a few cases I have seen this mechanism go wrong and output going to the wrong port. This includes the onboard output even though a card is fitted.

Then on another PC Create Windows 10 Installation Media , plug it in and power up while pressing the BIOS Boot Menu Key,  boot as a UEFI device if offered, follow these steps for a Clean Install Windows 10 making sure to delete all partitions down to Unallocated Space to get it cleanest. 

The Factory Reset just reinstalls the bloated factory install which no tech enthusiast would run in the first place because it's a terrible install.  You'll get a much better install following the the link which is the finest install of Windows one can have.

Feel free to ask back any questions and let us know how it goes.