Shuts down after a few seconds

[Cetacea]

Ok, so here is the problem.  My computer recently started to shut down suddenly.  Well, I downloaded one of those programs that see how hot things are and it was obvious the cpu was too hot because when I had a giant fan blasting into the side of the case I didn't have the problem any longer.  So I ordered a few more fans and some Arctic Silver 5, which all came in today.  So I put in the new fans and I took the heatsink off and cleaned it and cleaned off the top of the cpu heat spreader and I spread on the Arctic Silver 5 just like the directions said to do.  I put a grain of rice sized glob on and used a credit card to spread it evenly around the top of the heat spreader.  I then put the processor back and put the heatsink fan thing back on top.  Plugged everything in and turned it on.  It got as far as the screen that says what it detects and it said that the CMOS is wrong and then shut down before I could do anything.  I have reseated the processor, and cleaned and redone the thermal paste thing again.  I have checked the connections and I have reset the bios like it said in the manual by movinig a jumper.  I have tried unplugging all my fans in case it was the power supply but still I every time it gets to that one point it shuts down.  I just don't know what it could be.  Any help would be appreciated.   :-?

[Backdated]

Did you use static discharge precautions?
Are you sure that the processor was clean?
Is everything firmly seated?

All you can do is strip everything out (Disconnect both power and datas cables to all drives) except:
One known good memory module
One known good graphics card (Preferably PCI)
One PS/x keyboard
One monitor

If it boots now, replace things one at a time until it falls over. When it does, you've found your culprit.

[GX1_Man]

How about some details on  the system. If this is an AMD processor it could have toasted.  

[Cetacea]

Well, I thought I did the static thing but I suppose it is possible that I messed up.  The processor should have been clean, I didn't touch it where it would dirty it up.  Everything is firmly seated.  I tried stripping down to the bear stuff, but it still dies at the same point.  Is there any way to know if the processor or mother board or something else is bad without testing them out with other stuff?  This is so frustrating.  

[Cetacea]

It's an ASUS P5P800 motherboard with an Intel Pentium 4 3.0Ghz processor with the hyperthreading thing.  I had an AMD in the past that fried, it seems like it is fine.  It looks fine and doesn't smell burnt or anything.  

[Backdated]

Without some pretty expensive kit, substitution is the only method that I can think of.

[GX1_Man]

Intel chips are made to shut down if they get too hot to prevent damage. A built in safety net.  

[Backdated]

I've seen a P4 run without a heatsink for quite some time and survive (It shuts down of course) while an AMD blew virtually at switch on.
I still like AMDs though.

The penny drops..... Time for a rest I think!  

[Cetacea]

Is it possible for a chip to get so hot it shuts down within 10 seconds of being turned on?  I had it running before even though it was hot, you would think with the new thermal goo that it would work even better now.  

[Fed]

It is hard to imagine that it could overheat in just 10 seconds unless there is a major problem.
Do you have a voltage selector on the back of your power supply unit?
Is it set correctly for your mains supply?
Can you get into bios and set it to fail safe?

[Cetacea]

Seeing how I didn't touch the power supply I am sure it must still be set properly.  As far as getting into the bios, I can't because it turns off before I can do anything.

[Backdated]

Remove the heatsink assembly, very carefully clean off all the heatsink compound using a proprietary cleaning fluid and start from scratch.