Using a SPST you'd have to flick it up and then back down, it would work but it wouldn't be ideal. You need a momentary switch if you want to be able to just hit it.
or simply rig the key switch in line with the ground of your momentary switch. Then you can lock the computer on or off if you wish by disabling the momentary. But yeah, to use it as a power button you'd have to switch it closed and then back open.
You could still use the key switch and leave it in the closed position when you start your computer. I know this usualy make the computer shut down after about 4 seconds, but when I reformated my A7N8X-D computer and i had a keyswitch to power it, I could leave it in the closed position without the computer shutting down/restarting.
hey, how about this? pretty perfect no? http://www.switches.shopeio.com/inventory/details.asp?id=886&cat=Switches&sub= Part #Y10812
Thats perfect, it should juet snap back to the *OPEN* (Unswitched) when you stop turning it. Nice find
you could probably use an ignition switch that is meant to flip itself back after the alternator has turned.. like in a car.
Like they are saying use one that is meant to flip itslef back like ignition in a car, that should work fine then rig it so you can lock in the on positiion- no accidental bumping off button.