Help! Computer wont post or power

[Thrasis]

Ok, here is what I have in front of me.

First, I am a geek. I've been working on PCs since the first sound blasters and 8088's. I'm not a trained tech or anything, just a hobbyist. I don't know everything, but I know enough to be dangerous.

I decided to go to water cooling after a life of air cooling. Ripped my working machine apart to put in the top mounted radiator and pump, etc. While I was at it, I opened up some of the grills for better airflow, etc.
Finally received all my WC parts assembled my loop (CPU, VID, temp probe, rad, pump & res). Reinstalled & jumpered the power supply to let the system run. No leaks after about 18 hours or so. So I started to reinstall MB & everything. Used Ceramique (I've been using for a while and like it). reinstalled everything that was working before the mods (same ram, vid, cpu, nic, sound, etc.) Finally got the last thing together and pushed the power switch and nothing happened.
Hit the switch on the PWR supply to see if I bumped it in off position. Nothing.
Reattached all cables to MB to see if I didn't have something down all the way. Nothing.
Pulled apart the switch on the front of case & tested with a multimeter. It works.
Looked everything over again. Nothing seems out of place.
Unpluged the ATX and jumpered it to see if PWR supply was acting up. As soon as I did, pump, fans, fan contoller, everything lit up and ran. So I plugged it back in to the MB and hit power again. Nothing.
Pulled my NIC, Sound, and Raid card and hit the switch. Nothing.
What is going on here? I'm at a loss. Did my previously working MB bite the big one? Did I miss something.
Also, the PWR supply is a Seasonic 550w modular so it should be able to juice the little extra added by the pump. Everything worked fine before even in heavy gaming or photoshop.
Please help. I think I'm loosing it on this one.
Thanks to any and all who try to restore my sanity.

 

[Thrasis]

Oh. just for clarification, when I say it doesn't do anything. I mean nothing. No beeps. Fans don't kick. Doesn't start video. Nothing. It just looks like a $1200 paper weight.

 

[Tmagic650]

You are going to have to revert to basics here... The system did run for a while with the water cooling in place?

 

[Thrasis]

Nope. Never ran again after reinstalling. And it isnt like it's overheating either (failed cooling) there's just nothing. Has me baffled.

 

[Tmagic650]

It sounds like the CPU has been damaged or is dead

 

[Thrasis]

I happen to have another (older) CPU that will work in the board. I'll try that this afternoon. But a dead CPU would keep the board from booting entirely?
I guess what I'm wondering know is that my new CPU block has four thumb screws - it said not to overly tighten, I just finger tightened them - but maybe that was too much (just a thought).
I'll see if swapping out works.

 

[Tmagic650]

Yes a dead CPU would keep the system from booting or showing any signs of life. Good luck

 

[Thrasis]

OK. I tried another processor. I also pulled everything save video and 1 stick of ram. Pulled all sata / cables beside boot drive and power switch. Hit the power button and as soon as I did, a high, continuous tone comes from the motherboard peizo. But at least the fans / pump is coming on so something more.
Ok. Long tone I think Ram failure. so I switched the 1 stick with another. Same. and the for the next two sticks. Frustrated again. Non-ending tone and it would not boot any further but it's something different from before.
Thinking maybe the MB doesn't like the change from all the stuff I had to a basic system. So I pulled the power cable and pulled the MB battery and waited for a while (more like 5 minutes than the needed 1).
Reconnected and hit the power. Same thing. Never ending tone and no further. Any ideas?
I guess I find myself wondering again, Motherboard?
Oh if it helps, the Gigabyte is Award BIOS.
And Tmagic, just trying to help has been a line of sanity. Thanks.