reset...reset...reset...

Hi,

Have you cleaned the dust bunnies out of that units fans and the heatsink? It sure sounds like a heat problem. If that is not it, you may have to redo the thermal paste between the CPU and Heatsink. Are all fans running? You might also consider taking the side off of the case, blow a house fan in there and see if it stays on longer. Some times that gives us a clue.

still a no go...

Dust bunnies are gone, new thermal paste, all fans running. I left if off overnight and tried it in the morning so there would be no heat issues. I got about 8-10 seconds before it reset, then it just continues the cycle. Another 10 seconds and reset...

Have you checked the reset switch on the front of the box? And the reset connectors on the mobo, may be shorting out. You could try completely removing the reset switch cables off the mobo to be sure. ( You can shutdown as normal by holding the power button down for 5 seconds ).

reset the cmos
have you tried safemode

can't get there

it wont stay on long enough without reseting to get into safe mode. I will try the cmos.

If a CMOS reset doesn't do the trick then I suggest attempting to boot it with the board outside the case and sitting on a non-conductive surface such as a wooden tabletop or a piece of handy cardboard. Can you tell us more about the PC such as make/model (if a prebuilt) or the motherboard make/model?