No signal to monitor after a couple of minutes running PC

afrokid · January 16, 2021

This problem is unlike any other I have seen or experienced in my life. I have been building PCs and fixing them for friends and family since forever. I need insights into what may have caused it and why it still persists. I only created an account today because I could not find any resource on this and the results I get were the run of the mill general windows 10 troubleshooting guides. So here's the story -

I have a gaming PC hooked up to a dell monitor which supports switching between 2 different inputs using HDMI. So far, the second input has been unused since I built this machine 3 years ago. Recently, due to new work from home orders, I opted to buy a HDMI to USB-C dongle so I can hook up my laptop to the monitor as well, during work and switch seamlessly between either machine. I received my dongle in the mail and proceeded to connect the laptop to my monitor. After a while I tried to switch to my PC. The monitor immediately showed me a 'No HDMI 1 signal' even though my PC is visibly still powered on (keyboard, mouse and RGB lights all still showing activity) and I don't enable sleep or hibernate on my machines.

I proceed to hard reset my PC and the PC turned on and booted into Windows as normal. I use for it a while and all of a sudden, the monitor throws me 'No HDMI 1 signal'. I keep hard rebooting and after a few minutes of using it, the monitor displays the same message.

I troubleshooted the HDMI cables first. Maybe the one the PC had finally died. I switched it with the one connected to my laptop. Made no difference. I connected the PC to the 2nd input instead of the 1st. No difference. I connected the HDMI cable to the second HDMI output on my GPU. Still no difference. All this time, my laptop still actually works fine with my monitor on either inputs. So, end result is my monitor is fine.

Since yesterday, whenever I would boot, I couldn't even get past the Windows login screen. I wasn't able to even input my password. After a while, it was showing me a BSOD informing me that a critical operation died and restarted. The restart would land on the BIOS where my BIOS was showing me a single 54000 MB RAM stick on the 2nd of the 4 slots (i only have 16GB installed). That made me reset the RAM sticks, trying the other slots and putting them in 1 at a time to make sure my RAM sticks were fine. Still the same. I also reset the GPU to make sure it wasn't loose.

I finally opted to then reinstall Windows 10 today. The setup went ahead as normal and I was able to boot into it. As a 1st step, the first I did was to go to AMD's site and download the GPU drivers. Just when the download started, the monitor turned off and I was again met with 'No HDMI 1 signal'. I tried a hard reboot as usual but there's no signal at all to the monitor.

After all this, my only conclusion from all this is that, somehow connecting the laptop to the second input somehow borked one of the parts on my PC (how that happens I don't know). What piece was borked is what I am confused about since a GPU dying wouldn't have given me that weird RAM stick error in the BIOS or the fact that Windows was somehow corrupted. Anyone who has had this issue or can point me to the exact reason for it happening, please do share. I don't want to go out and buy a whole new machine without knowing what I need to replace in the first place.

My PC configuration for brevity: