Thanks for your reply... I actually did reseat the CPU daughter card. Cleaned mounds of dust from under the logic board and still nothing.
But... I just bought a replacement CPU daughter card off eBay for $9.99. What you are describing could still be the same problem, basically no CPU found at boot -- in your case, mis-seated, in my case fried (hopefully).
It's amazing a CPU is only ten bucks while a refurbished PSU is over a hundred. I wanted to try the CPU first. Next, logic board then lastly PSU.
now just my two cents, but i dont think replaceing the cpu card will fix it (it might it might) just a few trouble shooting ideas:
did you remove ALL cards (yes even the vid card) and attempt to boot?
did you remove all harddrives except the boot drive and attempt to boot (with only the vid card)?
did you try unplugging the comp pressing the power buttion for 10sec then plugging back in?
did you try replaceing the PMU battery?
did you try a boot without the PMU battery?
did you try removeing all harddrives and booting to see what happend?
does the psu fan spin up? (hold down the noisy main fan with a pen or something and see if the psu fans spinn up)
personally im thinking dead or dying logic board, or dead/dying psu...but thats just my 2 cents
**edit** where did you find that dual 867cpu card for $10? link?