Question PC shows no sign of life when CPU is inserted

Sep 24, 2021
My specs:
  • Ryzen 5 5600x
  • MSI MPG B550 Gaming Plus
  • 2x 8 GB Gskill Aegis DDR4 3200
  • 750W MSI PSU
  • 240 Galahad AIO
  • Saphire R9 380x
  • Lian Li Lancool 215
I build this PC about a week ago and it ran without any problem. I turned the PC off earlier today , took a nap and now he wont turn on anymore. No fans or mobo LEDs or anything, literally 0 reaction.
After a lot of trial and error Im currently in the following situation: When I remove everything from the mobo the PSU will turn on and lights and the CPU-LED on the mobo will turn on. I can also add the RAM and the M2 no problem - but as soon as I put in the CPU I get no signs of life again. I already flashed the board once with the latest BIOS update from the MSI website, any idea where I could go from here?