In an attempt to diagnose what's wrong with my PC (not turning on at all; button doesn't do anything whatsoever), I've stripped everything down to bare bones: Mobo, CPU, PSU (no GPU, tried with both RAM, and alternating individual sticks of RAM in different DIMM slots).

After a lot of testing I think it MIGHT be the power supply. So I'm borrowing a tester PSU from a friend of mine, and I'm gonna keep everything on a cardboard box work bench at first.

My question is whether or not I should start testing the "new" PSU (which I know works) in a bare bones configuration (mobo, CPU, and nothing else) or if I should try to fully build it out and then start removing parts from there if it doesn't work.

Right now, I'm not even trying to get into bios, I just want to see if I can get it turned on - period.