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
It might sound silly, but did you make sure the PSU power switch is turned on? Have you tried jumping the front panel pins on the mobo instead of using the power button? Made sure cables are securely plugged in on the PSU as well as the mobo? Tried plugging it back in to the original outlet that it worked at before?
I did try all those things as a sanity check. I also tried unplugging everything from the PSU and motherboard and plugging them back in and still no lights :(