Question Dell XPS desktop keyboard failure on boot/no way to enter bios

[Coupebuilder]

I have a well built older Dell XPS desktop with i7 processor, 32 gb ram etc. During a recent update it went into sleep mode and when I went to wake it I got the following message on a black screen:
Keyboard failure
press F1 or ......

Obviously cant get into Bios with no Keyboard.
I have tried the following with no luck yet

1. unplugged from power supply and drained with power button
2. removed battery and reinstalled new battery
3. tried several keyboards in all usb ports
4. reset bios on board with jumper
5. unplugged all ram and tried one at a time

any help would be appreciated.

 

[Deicidium369]

Since you tried multiple keyboards - hopefully on multiple USB ports - unplug the mouse and plug one of the keyboards into that port... Since you tried multiple keyboards with no change - sounds like an issue with the port (assuming USB). Tough one to diagnose

 

[Coupebuilder]

wireless mouse, and yes, tried keyboard known to be good in each USB with a reboot. Leading me to believe a bad motherboard, but strange to happen just after an auto update. I could see if it was BSD but this Ive never seen before.