mobo, cpu, or psu?

[Cienja]

I am hoping that you can help with this: When I power on the PC, the fan on my PSU, HSU, and the video card run for about 2 seconds then shut off, then on for 2 seconds, then off, this continues until I unplug the power. I troubleshoot until I find that when the main power to the mobo is plugged in only, then the fans all run normally; however, when I plug in the 4 "port" 12v power (near the cpu), then fire it up, the fans turn on, then off, then on, then off, and so on.

Hope all this make sense.

My question is this: Is it my PSU or the motherboard, or the CPU? The PSU is about 1 month old, the mobo is about 8 months old, and the CPU is a quad core duo that is about 1 year old or so.

Thanks for any input.

 

[cubeless]

gonna need a few more specifics on the parts...

p35 and 45 boards do a power cycle sometimes...

are u sure all your mobo plugs are plugged in good (pins push sometimes), and the vid card plugs?

reset cmos (unplug the psu and hit the power button first) next...

 

[Cienja]

mobo is GIGABYTE GA-G33M-S2L LGA 775 Intel G33 Micro ATX Intel Motherboard - Retail

CPU is Intel Core 2 Duo

Card is nVidia 8800GT

PSU is BFG 650w (BFGR650WGSPSU

When this first happened, I check the main power to the mobo and it was not plugged in all the way, so I did that. All the other plugs are in and good.

Thanks