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.
I admittedly haven't had much time to mess with it, but I confirmed the PSU is working, so I suspect the motherboard is fried. Still need to confirm that before I order a new one, and figure out why it happened so I don't do that again. I'm hoping my CPU is still fine.
I really appreciate everyone's suggestions, helped me narrow it down a bit
Just because the PSU works on another system (or God forbid, those awful "testers") doesn't mean that it's fine. PSUs tend to fail in weird, unpredictable ways