I will try and TLDR this as much as possible. Sorry!
a few days ago my PC got knocked over onto its side whilst I was moving my desk around (nothing major it literally just fell onto itself - FYI this has happened before and I experienced no problems) I nervously turned on the computer. Everything turned on fans, lights, etc. But there was no video displayed on my monitor. I switched monitors around, switched cables, and even tried plugging the cables into the motherboard (I have integrated graphics on my CPU). Nothing worked.
I then took apart the computer and made sure every cable was in its place, no pins were bent, and no warning lights. Everything looked fine on the inside visibly.
I then thought perhaps something was broken internally that I couldn’t see. I decided to just replace my motherboard. No change. I then decided to replace my CPU. No change. I am making one last attempt at figuring out what is wrong by trying out a new power supply that is arriving later today. I don’t have high hopes but I am really struggling here. Has anyone else had any similar problems and has figured it out? Any advice is greatly appreciated :)
I have listed below all of my PC parts:
ASUS Prime A320MK (I replaced the mobo with the same one)
Original CPU - Ryzen 3 3200g
New CPU - Ryzen 3 4100
RAM - 2 sticks of 16 GB (tried one RAM stick)
EVGA 700W power supply
GEFORCE 1080 GPU
As far as troubleshooting goes, until you can get at least a BIOS/UEFI screen on the monitor I would remove/disconnect all of your storage devices and only use 1 stick of RAM at a time. I would also unplug all of the devices connected to the USB ports etc (except for your keyboard).
It sounds like you have made sure the GPU is seated properly since you switched out the motherboard.
I am not sure if the new CPU you put in has integrated graphics (I could be wrong though), so keep that in mind while troubleshooting. You could try using a different output on the GPU itself if you haven’t already. (Try HDMI, display port, and DVI if you have the cables)
Does the computer seem to stay running while you have been testing it? Or does it shut itself down within a couple of minutes?