What exactly not working? 

You cannot boot into Windows? 

Or, BIOS does not Post? 

Are you getting any error codes on startup? ( red, blue lights or some beeping sounds?) 

Hi @driver7 welcome to this user to user forum. 

Has run the Dell F12 ePSA Enhanced Pre-Boot System Assessment diagnostics been attempted? 

Press and hold down F12 key during boot, the splash screen appears, followed by a menu. Use up and down keys to select, and use enter key to run diagnostics. Wait for hardware diagnostics to complete.

If hardware diagnostics detected a problem, this will be declared at first appearance of the white screen with is recommended solution. 

If no hardware problems detected, a white screen will appear, look in bottom right hand corner and click on Results. This will give a summary of tests performed and clicking on the left hand icon will give full test results for that hardware device. 

Please share an update. Thank you. 

To the posted a couple above, yes the machine posts just fine but it will not boot, it freezes when startup begins and after a couple of times having to hard-off the machine it attempts to run the automatic repair but that freezes as well.  I'm pretty sure I will have to do a reinstall.

I did run the thorough version of the diagnostic and everything checked out to be fine, it shows no errors.  I think at this point I need to do a reinstall of windows which I can't seem to do.  I'm typically very experienced in doing these kinds of things but the OS recovery tool doesn't seem to want to make a bootable drive.  I even stuck the drive into another computer and attempted to boot off it but it wouldn't.

Hi @driver7 thank you for sharing update. 

Have you tried creating clone OS (C:) drive from working computer and installing in 15 R3? 

If problem persist, remove all port connections, using bright light, visually inspect ports for damage, displaced copper strips causing a short, etc. 

Is the battery charging? Remove rear cover and locate dc port cable assembly. Disconnect connector from main board. If boot successful, this dc port cable assembly has a short and should be replaced. 

If you don't mind losing all your data then I'd suggest grabbing an 8gb USB drive and use the Microsoft Media Creation Tool to reinstall Windows on the drive. It will automatically format the USB to be a bootable drive. 

Your Windows 10 key is embedded onto your motherboard so once you complete the installation your Windows will activate. You cannot go from Win10 Home to Win10 Pro though, unless you then pay for the Pro key. 

During the installation you will get to a screen where you select the drive you want to use as your OS C: drive. You format this drive and click next to begin the installation. Formatting the drive removes all the previous data so you will lose everything that's stored on it. 

@crimsom 

 I thought about cloning it but I don't have another machine that has an m2 slot on them, this 15r3 is it.  The thing is, I originally bought this computer because I thought I was going to be travelling a lot, but it didn't pan out so it literally has been docked on a stand on my desk connected to 2 monitors except 5 or 6 times I've taken it down since I bought it new.  Only 1 USB port has ever been used and its been connected to an external hub.  I absolutely hated the way the power cord comes out the back so before I hooked it up for the first time I created a clip to hold tension off the PSU connector/cable. 

The battery does charge, since trying to fix this thing i've recharged it twice completely and drained twice while working on it.  I looked at the USB ports, they looked fine, ill try the PSU disconnect.

One other thing I've tried, I downloaded a Linux Live CD Distro and threw it onto a flash drive and booted it on another computer.  That let me download the Windows ISO directly from the Dell website, apparently if they detect you're using a non-windows based browser you get different options on the Dell OS recovery webpage.  I burnt the ISO onto a flash drive but it does the same thing...  Freezes during boot, im going to try it with another flash drive shortly.

@mattyb3 I'll give the Microsoft tool a try as well.

I don't like cloning. It can clone any issues from the old drive to the new one.

If you do create a bootable USB drive, stick it in the laptop and press F12 while booting to get into the boot menu. Select the USB and the installation will start. 

A couple of updates, I found that one of my USB flash drives had a ton of write errors thrown when I did a 1 pass test w/ Rufus, the other one went off without a hitch so I've set aside the bad drive.  But it still didn't work lol...

On @mattyb3 advice, I tried the Microsoft tool for creating flash drives and I can report it at least tried to boot off the flash drive.  The windows logo pops up and the status circle starts spinning then I got thrown an actual error for for the first time instead of just freezing and it doesn't look to be a good one.  "whea uncorrectable error", from what I've read it points to a hardware problem. I tried resetting the BIOS to default settings and made sure the overclock was disabled but it didn't help.  I don't know if a bad USB flash drive can cause this or not but i'm going to pickup a cheap drive and give that a try tomorrow.

Hi @mattyb3  cloning OS (C:) drive from a different fully functional Dell computer is advocated. Agree that cloning driver from the computer's original OS (C:) drive when it has problems is not recommended. 

Good luck! I really hope it's not a hardware issue. If you can get into the F12 Boot menu then I would suggest to run the ePSA Diagnostic to check for hardware issues. It doesn't always find an error but it could help. 

@mattyb3 Thanks for that, and yes I have done the diagnostic even the thorough version of it and it found no problems.

I did go pickup a fresh USB flash drive but it freezes all the same so I tried disconnecting the PSU from under the back cover and that didn't help.  Next I reattached it, then I started eliminating hardware 1 by 1 starting with m2's and the 2.5" drive, it didn't help.  Next I tried it with only 1 of the 2 sticks of ram then I switched them, it didn't help.  I removed the Wifi NIC and that didn't help either so I guess the machine is dead.  RIP AW 15r3 2016-2020, it was a great machine.  Thanks for the help guys.

I'd hate for you to give up on it. Have you tried to use a new M.2 or 2.5" drive?

Send it my way and I'll try to resurrect her

On @Alienware Area-51 ALX 2006 advice I tried to do a BIOS recovery but it didn't seem to want to start.  So plan B I downloaded the latest BIOS from the website and started a BIOS update via the boot menu.  It went off without a hitch, it restarted I entered BIOS setup menu reset everything to defaults and tried to reboot.  More of the same, when it tried to boot off the SSD it tries to start the automatic repair but freezes right away, with a similar result when trying to boot off a Windows 10 USB flash drive.  So I'm back to it's dead. 

In all my years of working on computers ~25 years, I've never had anything like this happen with a computer that would still POST.