I have a PC that I had replaced the motherboard, and was going to test to sell, but it wouldn't boot. It did turn on for a second when I accidentally unplugged a fan from a 3 pin port (now that I think about it thats probably not actually a fan port), then Immediately shut off again.
specs
Dell Optiplex 390 Motherboard
i5 2500k
16gb ddr3 1333mhz
240gb ssd (Windows 10 pro)
500gb HDD
gt 1030
EVGA 450w psu
1x case fan
2x rgb UpHere fans