ok im building a computer for an uncle of mine in mexico but it wont power up i have checked all the conection 3 times and then checked the mannual but i get the same problem it powers for a few cpu fan spins for 3 SECONDS and then the computer shuts down it does not power up at all the fan spins and that is it i can see power but it does not start
im asking you guys for some help so LAY it on me

o and the computer i have is the same spc's as this on

i got a matsonic ms9307c series mainboard sis 645DX chipset pentium 4 mainboard

with a pentium 4 celeron CPU 1.8 GHZ

1x 512 DRR  

radion 9200

400 watt power

and a 40 gb hard drive segate

2 things I can think of:

1) U put connector for pwr switch in wrong
2) Ur PSU is overloaded or not switched on in the backAnd these are all new components? You don't even get to POST? Are there any beeps?

Have you ever assembled a computer before? Have you tried removing and reseating everything?

I GUESS you COULD try to swap out one component at a time with known good ones. Have you stripped it down to motherboard, CPU, smallest stick of appropriate RAM, generic PCI video CARD and floppy?