Did I kill my mobo (D850GB)?

My first question is how do I know if my motherboard is dead?

All was running good, then decided to reinstall windows.

Actually, I first installed windows on a back up 10 gig drive for my Tivo (that's another topic). And all went well.

Then removed that drive, installed my original drive so I can reformat and start over.
It started booting up, then I realized my Windows CD wasn't on the tray, so I quickly inserted the disc, held the power switch (while it was still booting) and the machine shut down.

That's when it went to the dump.

I cannot restart the machine. Though pluggind and unplugging the ac plug makes the fan on the CPU and video card spin as well as the hard drive spin for like 3 seconds. I see a green light on on the motherboard.

I was able to start up windows ONE TIME. This was the windows that was currently installed in the machine.

I cannot figure it out.
I've been messing with making sure I got the power switch pin on the right pins.

The motherboard is a D850GB. It's like two years old that uses the old Rambus rams.

I know "if it ain't broke, don't fix it". But too late for that now.

Is it my PSU? Did I fry my board by pressing on the power button while it was still booting?

Any advice would be appreciated.

Thanks.

I don't understand it, but it works (for) now.

???????

Oh well, I'm not going to complain.