[NAME]  Reboot with the stock keyboard connected and make sure that's working correctly. Then restart the PC again with stock keyboard attached and start tapping F2 when you see the Dell splash screen. When BIOS setup opens, find the Keyboard Errors option and disable it. Don't change anything else in BIOS setup, but save the change to the keyboard setting and exit setup. PC will automatically boot when you exit BIOS setup. Back at the desktop (re)install the BT keyboard. Then do full a power-off shut down, not just a Restart in Win 10. When power is off, disconnect the stock keyboard and connect only the BT keyboard, and power on.  You get the keyboard error because the PC can't see any BT devices until after Win 10 loads. So the the pre-boot diagnostics report there's a keyboard problem. You shouldn't see that keyboard error message once you disable the setting in BIOS, and PC should boot normally with only the BT keyboard attached.  NOTE: You won't be able to use F2 to open BIOS setup or F12 to get to the boot menu with only the BT keyboard connected, so keep the stock keyboard around just in case.... The 2,3 blink code is a memory problem. With stock keyboard connected, reboot PC and start tapping F12 when you see the Dell splash screen. Choose the option to run Diagnostics and run all of them, including RAM. Copy error messages, if any. Since you saw the same blink code with original and replacement motherboard, it's possible you have a bum RAM module. If the diagnostics report a RAM problem, have Dell replace the RAM modules this time. If no diagnostics errors, but that same code comes back, power off and unplug PC. Now press/hold power button on PC for ~15 sec. Open case and carefully reseat each RAM module in its slot. See if that solves the problem. If not, have Dell replace the RAM modules.
Brand new XPS 8940 took delivered Aug 16th, On Sept 8th I noticed that the power switch was blinking (2 White Lights and 3 Amber) and opened a ticket with Dell Tech Support. I was told that the Motherboard needs replacement and they will set up a home visit to repair.  The new MB was backordered, so it was not until Sept 21st that I that a tech from WorldWide TechServices came to my home with the new MB replacement (Dell part #0427JK).  He worked on it for over 2 hours, and when he went to boot up, he had issues. He called Dell Support, and all he wanted to do was reinstall Windows. I could not understand why windows did not boot.  The screen that they were stuck on was the Windows Boot Manager.  The Dell support associate asked me if I had any backups or if I cloned the new drives.  I told him I had yet to do as I was still installing software and hardware.  I was planning to do it once everything was setup. All the Dell Support manager wanted to do was charge me $$ to create the backups of the “C” OS drive and additional drives installed on the computer.  I did not want to go through setting up the computer and install all my programs again….  He said he would have someone from Dell call me the next day to talk about this.  Once he hung up, I asked the in-home tech to show me what and how he was booting up.  He did, then I asked him to go into the Boot Menu by pressing F12 during booting.  He did, and I told him to boot using the “second” option which was the “C” drive.  Low and behold my home Windows screen came up.  All seemed good… and the tech left. The next morning, I went to turned on the computer and the Dell SupportAssist | Pre-Boot System Performance Check had a “Warning Message that Keyboard not found”.  Moments later the Dell Logo comes on and it booted “normally”.   I do have a Bluetooth Logitech MX Keys keyboard previously worked with no issues before.  I uninstalled the Logitech keyboard, rebooted again with stock Dell keyboard and reinstalled the Logitech but I still get the Pre-Boot error message.  How can I get that Pre-Boot “error message” to no longer show?  It just very annoying and should not be there.  Finally, I did notice that the same error lights (2 White Lights and 3 Amber) were blinking.  After I rebooted the error did not return, but this also has me worried for the long term health of the MB.  Any thoughts on this?  [IMAGE]  COMPUTER SYSTEM XPS MT 894011th Gen Intel(R) Core (TM) i7-11700K processor (8-Core, 16M Cache, 3.6GHz to 5.0GHz)NVIDIA(R) GeForce(R) GTX 1660 SUPER(TM) 6GB GDDR6360W Night Sky Bezel Chassis including optical driveWindows 10 Home English16GB, 2x8GB, DDR4, 2933Mhz512GB M.2 PCIe NVMe Solid State Drive + 2TB 7200RPM Hard DriveSAMSUNG 970 EVO NVMe M.2 1TBAdditional 1TB 7200RPM Hard DriveI also have dual monitors set upLogitech MX Keys KeyboardLogitech MX Master 3 Mouse
XPS 8940, new motherboard installed, new problem