I thought about just leaving the power supply (and its fan) on, but I hoped to be more green. A similar solution is to use an external brick instead of the built-in power supply. At least then there won't be a fan running all the time. The switch idea works, but then I have to operate two...
I have a mini-ITX MB (Intel D945GSEJT) that I would like to power from the power supply that came with my case (Winsis Wi-12). The board has only a 2x2 (P4) power connector. The power supply will not activate unless the main (P1) power connector is plugged in and pin 4 is connected to ground...