No power after RAM update
New iMAC 27" 2020 desktop. Attempted to increase the RAM from 8 to 64 following Apple directions using MacSales OWC chips. All chips were properly seated. Plugged the computer back in and there is no power response at all. Not just the 'black screen'. No indication of any power up. Checked the outlet and power code and all is functioning properly. I then took out the new RAM and put the original RAM chips back in with the same result. The computer is now dead.
Suggestions?
iMac 27″, macOS 10.13