Abit AB9 Motherboard problem

[Deez]

I have built this PC about a year ago, and just recently I have began having problems with overheating on the processor.

My system is:

Abit Ab9 Motherboard

Intel Pentium D 915 2.88 GHz (what the motherboard runs vs rated speed of 2.80)

3 Gb DDR2800 ADATA Dual Channel Matched RAM (2x 1Gb + 2x 512Mb)

ATI x800SE

ThermalTake 550W Powersupply

Thermal Take cooler rated to run Quad core Extreme as I know the Pentium D's run a bit warm.


So the initial problem was the fact that in middle of playing need for speed my PC just shut off....no beeps no nothing, just "click" and it was off. So I let it sit then made sure that all my fans were clean and that nothing is blocked as far as airflow. (I have the Antec 900 Case) Cleaned and reseated the heatsink using my antec thermal paste. Now I can not even make it through POST without it over heating and shutting down ( >115c ) So before I start throwing money in the wind I am wondering if anyone has run into this before with this combination, and also wondering if the board is going or the CPU.....I have a spare CPU to test my theory with, but its a celeron but hey it may work fine to test. I am planning on replacing my video card in the next few months, and wanted more input as I may be replacing about 90% if I am right.


Thanks

[BUFF]

if you can't even make it through POST how do you know that it's shutting down due to temp?

what POST codes does the LED reporter display?

[Deez]

I know this as when I first put everything back together after it shutting down while just surfing this time I went in to try to underclock my processor to try to lessen the heat effect and I checked the monitor and I was at 109c within 30 seconds it shut down. I waited about 10 minutes then attempted to turn it on again and it barely showed the splash screen and shut off. Also worth noting when it is being rebooted it runs both the HD and DVD burner indefinately as it sits waiting to boot.