Z170m Extreme 4 will not POST; RMA?

I?嚙緞e been fighting a new build for the last several days and have run out of ideas.

I?嚙練 about ready to RMA this board, but thought I?嚙範 come here for any final suggestions any of you might have. This is the first and only AsRock product I have ever owned.

The new hardware is:

AsRock Z170M Extreme 4 motherboard, Intel i5-6600K CPU, a matching pair of 4 GB sticks of Hyper X DDR4 2666 RAM from the AsRock qualified vendor list.

Old hardware carried over from previous build that was working fine last Saturday:

Antec Solo II case, no video card, Crucial SSD for OS only, 3 spinning drives (WD and Samsung), Rosewill Silent Night 500 watt power supply, Samsung DVD burner, Microsoft wired keyboard, Microsoft wired optical mouse, Noctua NH-U12S cooler, Dell 23 inch flat panel monitor connected by DVI-D. It does not support HDMI.

Nothing at all in the PCIE slots. This is a simple, non-gaming PC.

Problem description:

It has NEVER posted. The case speaker has NEVER beeped. I get NO screen output. For a few hours, I did get the CPU fan to spin and I did get the hard drives to spin.

For the last 24 hours, I can?嚙緣 even get the fans to spin. No screen output and no signs of life.

I?嚙緞e done all the troubleshooting steps I can think of, such as:

Pulling all parts out of the case and re-assembling on a tabletop on cardboard.

Reseating the CPU and CPU cooler.

Cleared CMOS by 2 different methods, including twice pulling the battery for 4 hours.

Trying each RAM stick individually into all 4 slots, one at a time.

Trying RAM pairs in the recommended A2 and B2 slots.

Using 2 different power supplies, using just 4 pins on the ATX 12 volt header and also using all 8 pins on the ATX 12 volt header.

None of the above steps has made any difference at all.

Does anyone have any final suggestions I can try in the next 24 hours?

If not, it goes back to Newegg and I choose another brand.