This is what my Q35 board does on plug-in. It starts for a second, and shuts down, clanking the HDD. When I built it, after this initial powerup, it wouldn't switch on at all. Turned out my power switch was faulty. I wired my reset switch to the power switch header and it fired first time, every time.
There's something that many people get wrong that can cause this. Check that your power switch is working, and that you've not wired it to the wrong pins, or have wired your reset switch to it by mistake! If you think your power switch might be faulty, switch it with your reset switch, see if it fires with that. I rewired a new switch from an old case in my HTPC build, all switches are standard. I never throw wiring out from knackered cases, for times like this, it's good to keep around, LED's too..