After a BIOS update, the XPS 8940's power lights are blinking: two amber, one white, and n

Dear all, The i9 10900K CPU and Nvidia RTX 3070 video card are in my XPS 8940. I've noticed more fan noise lately than usual. I thought the noise was coming from the video card, so I took it out, blew off the slight dust, and then put it back in, but the noise persisted. The fan noise persisted even after I installed the most recent video driver (as well as the GeForce Experience, which I don't normally instal). I should have known that my M2 drive's fan was making the noise (an Ineo cooler with built in fan). I took out the M2 drive. removed the drive and cleaned the dust.

I eventually found myself on the Dell website after all of this fiddling and searching for the setting that regulates fan speeds. After selecting my device, I saw there were five suggested driver updates and a BIOS upgrade, so I downloaded and installed those.

My 18-month-old XPS 8940 is now completely unusable since somewhere along the line, something went wrong. When I turn it on, it does the "turns on for a couple of seconds, then off", so I did the real time clock reset thing, with no effect. I have a black screen, the computer will start, the fans will spin, then the power light starts flashing 2 amber and 1 white, which according to the service manual means "cpu misconfiguration or failure".

I've tried EVERYTHING listed here, including removing all of the cards, the hard drive, and the SSD, trying to recover the BIOS, using the Support Assist OS Recovery USB drive, using the onboard HDMI and Display Port video ports (the monitor is working fine), reinstalling the original M2 card that came with the computer (I've been using a larger Samsung drive), removing the CMOS battery, trying a new battery, and quickly pressing the F2 button with a wired.

To be really honest, 1) I dropped the little screw into the motherboard near the voltage control module when I removed the M2 drive. While the computer's power was turned off, the cord was still plugged in. 2) My drained eyes understood that I might have chosen my XPS 17" laptop when I was looking for my desktop in the list of Dell products, so I went to the "Check for driver updates or hardware issues", downloaded everything, and installed it.

Please confirm for me that downloading and flashing the COMPLETELY WRONG BIOS is not possible. 3) After downloading and installing the MSI Afterburner programme, I messed around with it for a while before realising the noise wasn't coming from my video card. I then shut down and removed the programme, and when I reopened, everything erupted.

I apologise for the length, but after reading so many questions with few information, I felt compelled to share everything that led me to where I am today. I would be grateful for ANY assistance that you can provide.