compuer turns on then imediatley crashs

[zacattack]

well i just finished puting together my computer with a few friends and when i hit the button to turn it on all the fans spin for a second then everything shuts off. then i need to unplug the computer for about 5 seconds then it can turn on for a second again

me and my friends checked the everything a few times andeverything seems right the only thing we could think of is the cpu.
it went in fine but when we were puting on the heatsink and fan the little square of grease (or w.e it is) was touched by my friend and alittle part of the corner rubbed on to my friend's hand.

the power supply is 450w
the mobo is an ecs nforce4 a939
i got 2x512 dual channel ram pc3200
the power supply is a 20 pin connector but the mobo claims to support 20 or 24 pins
i also have thec ati x800gt256mb gcard

what could be wrong??

thanks for the help

 

[sCribes]

my first thought would be the power supply, size seems fine, maybe its not working properly. Check all your jumpers ect..

take out every expansion card possible, so that you have only whats neccessary to run the system unit. One stick of ram in if you have more than that, etc.....

If it boots stable, then reinstall expansion cards one at a time until you find the problem. It could be a improperly installed card, or not pushed all the way in. I think you normally get a CPU error if the cpu is bad, but thats not always.

From what your describing, really sounds like the psu.

Does it POST?

 

[cedjunior]

Also, make sure the 4pin 12 volt is plugged in too. When I was building my computer, I forgot to plug that in and when I turned on the pc to test it, the fans and lights came on for about 5 seconds then it would just die.

 

[sCribes]

Also, make sure the 4pin 12 volt is plugged in too. When I was building my computer, I forgot to plug that in and when I turned on the pc to test it, the fans and lights came on for about 5 seconds then it would just die.

Good call man......i would second that idea.

 

[Cellbuster]

WTF my 4pin on my 20 pin is not connected and is working fine.
i had problems of crashing when i had it in.
my older psu had just 20 pins so i figured it was no big deal