I just built a system over the weekend, and everything was working fine. Once everything was installed, I decided to move it upstairs, so powered down as usual. No indications of any problem - normal shutdown of XP. I took the unit upstairs, hooked up all the cables, plugged it in, pushed the front power switch...and nothing: no fans, no lights, no nothing...completely dead. I tried several power cables and outlets - nothing. Took it back to its original location - nothing.
So I swapped out the PSU with a similar unit, same response. Pulled the power switch connector off the mobo and reconnected. Removed everything but essential parts. Still absolutely no response. There is absolutely no smell from the PSU. Could it be the power switch? How can I work around it? Any way to jumper the pins on the mobo so that it thinks the switch is on? I'm absolutely baffled here - it went from perfect functioning to nothing with no indications of any problem whatsoever!!

Here's what I've tried so far:
0) yes, I'm using a verified power source that passes the "lamp test"
1) tried 3 different PSUs - same result
2) disconnected everything; reconnected with the basics - same result
3) completely removed and reseated motherboard - same result
4) replaced power switch with an extra one I had - same result
5) tried shorting across the power switch pins for a moment to get full power - same result
Nothing works...this motherboard is completely and suddenly dead.

that's a very strange situation. by "power switch" i'm guessing you meant power cable? if not, try a different cable. and if even that fails, the motherboard may have died from unknown causes.

Yes, I tried a couple of different cables. In fact, I made sure the cable I was testing with would start another PC - no problem. By "power switch" I mean the actual momentary switch that triggers the mobo to full power. Since two switches give exactly the same result, I'm left to assume that something on the motherboard is hosed so badly it can't even control the power-on process.

well when u plug in the kettle lead to the PSU and have the socket turned on as well as the PSU you should see lights on the Motherbaord, so if you dont either the lead, PSU or motherbaord is dead

its unlikely its the PSU as you have tried 3 of them, so its either the Lead or the motherbaord, if i were you i would try another kettle lead, if no LED's on the motherbaord lite up still its likely the motherboard

As I said above, I used the same "lead" to power on another computer...this isn't an issue of power availability. There are no lights on this motherboard, so no help there.

hmm have you no other leads you could just try, may as well u never know, but it does sound like the motherbaord, but i know i had the same problem before and it was my lead.

i know logically if the lead makes another pc work then the lead must work but often computers have a mind of thier own

if that doesnt work then the Motherboard may just be dead,

I have tried 3 different power cords - same result.

it's most likely that the motherboard is dead. if you're sure that the power supply you're using works, then it has to be the motherboard. there's no other explanation that i can think of.

My final question is: could these symptoms possibly be the result of a fried CPU? I have eliminated everything else, including memory. Even out of the case on cardboard, this mobo is totally non-responsive. If a CPU problem could cause this, then I'm not sure if it's the mobo or the CPU...