Updates:
- Used a known-good PSU, no change
- EVGA 650 SuperNova is a G2, 80+ Gold Cert'd
- @barty cleared the CMOS, ensured no bent pins
- @barty 1 stick RAM right now, just to test POST
- @barty MOBO was second-hand via Amazon. It sucks, I intended to buy new, but Amazon makes it easy to...