UPDATE: I fixed it!! It was the PSU.
So I just built my first PC in like 20 years. Everything was going fine, I was installing Windows and got to the network setup step and my wifi was having trouble staying connected. I figured it was because I hadn't set up drivers yet, so I thought whatever, no problem, I'll just move it by my router and plug in an ethernet cable.
So I powered off and moved it, and...dead. Nothing is happening when I hit the power button. No fans, no lights, nothing. I've made sure no cables got jiggled loose or anything. Maybe I shorted something somewhere on the motherboard? I can't see anything without fully disassembling and having to rebuild it. I really don't want to do that, but I guess I'll have to unless I'm missing something obvious. I'll test the PSU tomorrow but I doubt it's that, these are all brand new parts.
Any ideas?
Specs:
AMD 7800X3D
ASRock B650E PG Riptide WiFi
Sapphire Nitro+ Radeon RX 7800 XT
2 x 16GB Crucial DDR5 RAM
Seasonic GX-850 PSU