Hello, Boydie66.
Does your problem still exist?
May I ask if you tried to cross-test with the previous PSU after the problem occurred when you replaced the PSU?
What is the current BIOS version used, the content of the setting in BIOS (or whether it is the default), the brand and model of your memory?
Are the unrecognized keyboard and mouse connected via Bluetooth?
In addition, according to your description and the appearance of Q-code 00 according to the link below, it is possible that the CPU or related components are not fully connected.
https://www.asus.com/support/FAQ/1043948/Thank you.
Due to the ongoing regional holidays, my responses may be slightly delayed.
Thank you in advance for your patience 🙂