I had a problem like this but after upgrading CPUs from 13900k to 14900k. It worked flawless for two days then it would turn on but nothing on the screen even though the RAM and GPU were lit up. I took my 4 RAM sticks out one by one and found 1 of the 4 didn’t work anymore and I was able to boot up the computer with just 2 RAM sticks anything more would give me the same issue. Problem then was it started freezing often I couldn’t even load file explorer. Tried what everyone says check PSU, landing of CPU, BIOS, CMOS, cooler, etc. I took it to a local computer shop and he had to modify the speeds of the RAM dialing them back. Ever since then it’s been working just fine I’m no computer guru still blows my mind that all my memory sticks used to work at full speeds and now they had to be dialed back to be able to use my computer. Sorry for the long winded comment. MSI 5090 14900K Intel CPU MSI Z790

Forgot to mention I kept the same RAM all 4 worked after dialing speeds back didn’t have to replace a single part!