Turning on Motherboard without case

On your board, usually on the bottom, are the pins you plug your case's power and reset buttons into. Read (in really small print) under those pins to find the power (pwr) pins. Bridge those two with a paperclip or key or something.  

^yup

some more info here http://hardforum.com/showthread.php?t=1260360

try googling before asking questions, the above took me 5 seconds to find.

As ArcticWonder said using Jumper at the power pin... (edit: fixed, short it using metal object)
read the mobo manual (layout diagram) for make sure it was the right pin...

OOT: Sorry but i'm not agree with u slicedtoad,

sometimes human interaction in forum better than hard cold google search  ...

BTW it won't shock you if you're touching the piece you bridge them with... In case you're wondering XD

I'm not sure that using a jumper to sustain a connection on the PWR pins is a good idea, the case 'power up' button is a momentary (it just pulses the connection),

its not a continuous connection after the button is pressed.

Using something like the tip of a screwdriver or a key to momentarily short out the PWR pins is the way to go.

Never heard of any problems using a jumper, but I like to play it safe.

yep, a momentary power jump is all ya need. just be VERY carefull that you and the components are all grounded properly - otherwise you'll have dead parts. also be sure to turn off and unplug (from the wall) the PSU before making any changes to all power or data connections between components.

While momentary is all that's needed, holding the bridge won't hurt anything (though it might not turn it on till you un-bridge, depending on the mobo). Holding the bridge should be the same as holding down the power button (which is used to hard-reset).

Keyword is sometimes. If you can find a directly relevant google result that answers your question...

+1

thanks for the fix, (My english kinda bad, I'm cannot find suitable word other than "jumper"   )

Well when I did my external build I just connected the case power button and used that to power it up...

Apologies if I made it sound like it had to stay connected... They don't have to.