Bootloop... Motherboard Issue? (Gigabyte Z68X-UDH3-B3)

Hello. I am new to building computers, and built my first rig about a week ago. I installed windows today, and rebooted after installing updates. Upon restart, the computer turns on for 2-3 seconds, and shuts of for 5. This cycle repeats indefinitely. Here is my build -

Intel Core i5 2500k Processor
Gigabyte Z68X-UD3H-B3 Motherboard
Nvidia GeForce GTX 570 Graphics Card
OCZ ModXStream Pro 600W PSU
Corsair Vengeance 16gb (4x4) RAM
Western Digital Caviar Black 1tb Hard Drive

The computer was working 100% - everything fine. I've tried a lot already, taken out the CMOS battery, stripped the components to the bare. Nothing seems to work. Just want some help - wondering if it's a motherboard problem (the infamous Gigabyte Z68 "bootloop" ) or possible the PSU/Processor/RAM.

When I turn the machine on, the fans start, the lights on the motherboard turn on, the heat sink starts up, and almost immediately shuts down (2 seconds). I cannot access the BIOS, as when attached to a monitor - doesn't show anything. I really need some help with this, I have tried so much. Wondering if it's a motherboard issue, and I should just return it/buy a new one.

Try to boot with only 1 RAM stick.

Try the RAM stick in different slots and than try another one.

Thanks again. Tried all 4 in all 4 slots - didn't work.

Does the CPU fan go into a real frenzy when you switch it on?
If it does, then you need to reseat the CPU and HSF..... the thermals are making it shutdown to protect other components.

Also make sure you haven't forgotten to plug the ATX 12V 8pin Power connector and the CPU HSF is connected to the CPU FAN header not any other fan header.

Try to breadboard it.

Just forgot, check and see if the PSU fan comes on or not after you try to start the rig.

One more thing to note. I bought the parts a week ago, and built it. Upon the first startup, I changed around the BIOS for a hackintosh (as I am planning on dualbooting). I changed it to AHCI mode, and set HPET to 64-bit mode. My ACPI suspend type was S3(STR). Turned out, the hard drive I had installed was dead. I left the machine sitting for a week, and my new hard drive arrived yesterday when I installed windows, and the machine failed. Just telling you guys about the BIOS changes - I am really a newbie and unsure if those should affect the machine, taken I switched out the hard drive.

I will try. And yes - the PSU fan DOES come on when I power it up.

No I do not have chances with either. As a last resort, I can scavenge something from some old computers I have laying around.

I would try that with PSU.

Do u have mobo speaker? Any beeps?

Not sure if there is a speaker... there are NO beeps.

Again? What pins?????????? It's a pinless processor.....

You have to remove that board from the case and breadboard it. This could be a short on the backside someplace.

Very good idea. Thank you. I will try that in the morning - as it is almost 1AM here. I'm signing off for the night - thanks for all the help.

Oh OH...... Get it out again, check very carefully AGAIN. Inspect the whole socket and the processor edges. Post a PIC immediately here if possible, look at the underside of the processor where the contacts are, check for burn marks and discoloring on both the Mobo CPU socket and the Processor Contacts.
Post pics if you can.

Correct.

Thank you. Will do. I have a few questions though -
How will I power it on without a power switch?
All I should have - processor, motherboard, PSU?
Only cables I should have in are Processor fan, motherboard 24 pin, and motherboard 8 pin?

Your mobo does not have a ON/OFF button?

No the Z68-UD3 does not have any buttons on the Mobo, not even CLR-CMOS , reset or power.

No it does not. As the other guy said - I will use a screwdriver and short it.

That will do fine.

Going to sleep as well : )

I would try to replace the PSU.

Yes, ASAP : )

BTW, Frys have a price match, they match Amazon and Newegg.

I know, for large store like Frys, they have poor selection of the mobos.