Intel Q6600 2.4GHz - OEM
GigaByte GB-P35C-DS3R
Seagate Barracuda 250GB 7200 RPM SATA-300 Hard Drive - OEM
Samsung 20X DVD-RW etc - OEM
EVGA 8600GTS 256MB (temporary, 8800GTX is in mail)
Patriot 2x2GB Extreme PC2-6400
Antec True Power Trio 650W
Zalmon 9500 cooler
Antec 900 case
 
When I power on the system it runs for ~8 seconds and then the power shuts off. ~4 seconds later it powers on again and repeats.
 
I disconnected/reconnected everything. I took out and re-seated the video card.
There are no signal beeps from the Mobo, no signal on the monitor.
I have a service req in with Gigabyte but they are taking their time responding, and I figured I could get at least as good info from this board, if not better.
 
Any help, no matter how silly, will be appreciated,
Thanks,
Evan

Is your cooler installed correctly? If not the chip gets too hot and shuts down in a few seconds.
take the MB from the case. install cpu, heatsink, and videocard and one module of ram. then see what you have. If it posts then your on your way. if not, then switch out the ram stick for another and try again. or try a different slot.  
I dont think its your videocard. your machine would still run but you wouldnt see anything on the monitor if that was it.
did you se thermal grease when you installed the heatsink? Is the PSU new or from another build?

New CPU and heatsink. I used thermal grease. If I take off the cooler I don't have more grease to put on. Is it really credible that the CPU could overheat in 8 seconds without any processing load?
 
The cooler install is pretty straightforward. I cannot imagine how I could have screwed it up.
 
PSU is new, and the first thing I did when the power cycled was to swap in a different PSU. I will try removing a RAM stick.
 
Are you suggesting that I try to boot it without the Mobo installed in the case?
 
thanks for the suggestions,
Evan

8 seconds is a pretty good run for a poorly mounted heatsink.
 
Start with what mweidler said, and be prepared to get some new thermal compound.  Shin Etsu, AS mx10 or as 5, in that order.  (they're all good enough)
 
Use the box your MB came in, and put the MB on the packing it came in.

Yes hook it up outside the case. much easier to diagnose and swap out parts. and you elimate any possible short from the case. start with a bare minimum. if it still doesnt post its one those few parts
buy a tube like croc said, that way if you have to reseat the HS you can.

OK- thanks again. I'll get on it in the morning.
 
Evan

GL... post if that doesn't work, but hopefully it will...

Okay! I pulled the mobo and reseated the cooler, no luck.
I pulled the memory and it stopped power-cycling.
Put 1 stick back in and it continued to run without stopping, still no boot.
Reset the CMOS and bingo! It Lives!
 
Thank you all so much! This is a fabulous community.
 
Also the 8800GTX arrived today from zipzoom. They have a great price ($350 after MIR.) I would snatch one if you're looking for a card.
 
Evan

You better set the RAM at specs or your gonna run into trouble again.

They run at 2.2V, default is 1.8
 
Thanks for the tip!

Your welcome.

All I got is that I have had similar issues with power supplies.  If you switched to a known good power supply and you have ensured that there is no short, then you have to start trying out main components until you find the culprit.  Is your ram on the qualified vendors list?  If not, try some ram that is.  Does your board need a bios upgrade to run that chip?  You may need to do that first.  Is is possible to check out the CPU?  not a bad idea.  
 
Oops... missed the part where it lives.    

Well thank you anyway!
 
Evan