I'm dont think this is the best forum for this, but I thought this was the best fit. I have built computers before but this has never happened to me.

Event: I turn on the computer and it'll automatically turns off.

How it all happened. After putting all the components together checking and double checking everything is connected; I turn on the power (stays on for two seconds, nohing on screen) and then it just turns off. I so take off the heatsink, unlock CPU look at (nothing wrong there I hope), lock it down, put the heatsink back on, plug everything back in, and turn on the power. This time I get through the screen telling you whats on the computer and to the DOS looking screen (if fugred great; must have fixed what ever the problems was). So i restart, and go into the BIOS, and start the changing the boot sequence when the computer hangs and turns off again. Now I sit dumbfounded. So I keep trying turn it and the it goes and turns off. Then thought it might be the CPU temp, so after i get into the BIOS it says its only 90F degrees and then turns off. So my next solution was to go down to Frys and pick up a power supply and same new motherboard. Comeback try new items bought and the samething happens. So i figure it might be a faulty case power switch and take back the case and power supply, motherboard to frys. When talking to a person at Frys he told me the porblem might be the RAM, thought about it and said he could be right. So i buy a new case and RAM. Comebck and to no avail the same thing happens again. I am completely lost, getting frustrated, and spending too myuch money on gas for these trips. If anyone could help that would be great.

Here are the components during different attempts:
1st Attempt:
AMD XP 2400+ Plus (2.0GHz)
Thermaltake Volcano 9
MSI K7N2 Delta-L Nforce2 400FSB
2x SAMSUNG 256MB DDR Ram PC2700 333Mhz DDR
W. Digital 120GB (WD1200JB)
Lite-On (LTD-166S) 16x DVD
Lite-On (LTR-52246S) 52x24x52x
SONY 3.5 inch 1.44MB
ATI RADEON 9200 128MB 8X RTL POWER COLOR/DVI/CTR/TV out
Antec Lanboy 350W SmartBlue
Philips 170B2T 17" LCD

2nd attempt:
Switched out power supply and motherboard using same model power supply and same model motherboard.

3rd attempt:
Switched out RAM and Case
Corsair RAM 256MB PC2700
Enermax CS-307 330W power supply

Only during first attempt and 2nd attempt did I get to the BIOS screen. I have even tried just having the CPU and MB powered (no RAM, Video Card, mouse, keyboard), however I still get the same results (turns on and two seconds later it turns off).

Hello urstupid. Chances are you either have a grounded board or a backwards IDE cable. Try removing all the IDE cables and recheck to make sure no spare mounting studs are contacting the back of the board where there are no holes.

If removing the IDE cables works, reconnect them right next time.

<font color=blue>Watts mean squat if you don't have quality!</font color=blue>

I am stupid, as the name refers to. I should have won a Darwin Award. Instead of putting the thermal sensor under the CPU as the instructions said, I put the thermal sensor right on top of the core slabbed on with tons of thermal compound. Please, all I need right now is a good smack in the face, please be genlte though. Just wondering, why did it crap out like that?

Hello urstupid. Chances are you either have a grounded board or a backwards IDE cable. Try removing all the IDE cables and recheck to make sure no spare mounting studs are contacting the back of the board where there are no holes.

If removing the IDE cables works, reconnect them right next time.

<font color=blue>Watts mean squat if you don't have quality!</font color=blue>

The question is does it still work? Shorting the thermal sensor by sandwiching it between the hsf and cpu is supposed to shut the psu down before it does damage, but it dont always work that way.