Question I can't get my PC running after CPU upgrade

[Ovsz]

So I've had my PC for 4 year my PC consist of brand new an pre-used parts Well the CPU I've had the entire time was used an is a Ryzen 7 2700x. I bought a Ryzen 7 5700x an when I got done putting the fan on an turned PC on an everything lights up but my monitor doesn't display anything an after like 10 seconds it shuts off. So I thought it was a bio update problem so I put my old cpu in (booted right up no problems) an I updated my bios an when i tested it again it still showed nothing an turned off. Am I just that stupid not seeing the problem? My mother board is a B450 atx steel legends.

 

[Lutfij]

Welcome to the forums, newcomer!

When posting a thread of troubleshooting nature, it's customary to include your full system's specs. Please list the specs to your build like so:
CPU:
CPU cooler:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
Monitor:
include the age of the PSU apart from it's make and model. BIOS version for your motherboard at this moment of time.

My mother board is a B450 atx steel legends.
https://www.asrock.com/mb/amd/b450 steel legend/index.asp
^ is this your motherboard?

Did you flash the BIOS to the latest version prior to upgrading the processor?

Moved thread from Memory section to Systems section

 

[Ovsz]

So if I'm reading ur question correctly no I did not update my bio before switching out CPU the first time. I did update my bio after I couldn't get my PC to run more than 10 seconds but atm my bio is upgraded an my old CPU is in my PC currently running an still can't get my PC running after switching cpus