Looking at an Asus Strix Z790-E motherboard
Looking at an Asus Strix Z790-E motherboard
Your symptoms point to a damaged pin in the CPU socket. This is very easy to do if you don't drop the chip straight down and have to wiggle it around until it sits right. Your motherboard will tell you which two slots are needed for dual channel mode. If you can, upload some clear pictures of the socket so we might figure out what went wrong there. Usually, those bent pins can be fixed back with a small needle. If everything is working fine now, try running memtest. If it says no errors on a full pass, you are good to go. Check dual channel settings using cpu-Z.
I really took care when putting the cpu in. I tried two boards and they both gave me error code 55. My corsair h150 elite capillax has a box that shows up but the fans just won't spin. I connected power to sata, plugged into the usb header on my motherboard, and it still won't turn on.
Did you reset the BIOS after updating? What BIOS version is it showing right now?