Q304 issue that 2 mother boards and 2 HDD still can't fix

Hello ASUS owners, we bought a brand new Q304 from a big box store 50 miles away back on July 3, and paid nearly $700 for it. It's for a student heading off to school in a week. After opening the box and booting up I was updating the WIN10 OS and during one of the reboots it booted up to the BIOS and it appeared that it couldn't locate the HDD, after calling ASUS support and doing a hard 60sec reboot, it came up to the desktop and I finished updating WIN10, and ran a chkdsk to see if the HDD had any bad sectors. Everything was good.
Within the next 2 reboots it came up to the BIOS again and nothing it tried would get it to the desktop. I called back and got a RMA and shipped it out to Grapevine TX and they received on July 8. On July 18 I called to see what the status was and they said it was being repaired. After many calls and escalating the issue, we got it back on the 29th and I again booted and updated WIN10, and again it booted to the BIOS. I was able to get it out of the BIOS a few times but then got the blue screen of death a few times. I called and sent it back again and they got it on the 3rd of August and now they are replacing the HDD and the mother board.
Either they are getting a bad batch of boards, HDD, or something they have had this laptop in repair for most of 6 weeks and I still don't have a laptop for my student.
anyone with an idea of what the problem might be? I was thinking either a bad ribbon cable or memory chip or maybe just a lemon of a laptop.
thanks
gary