Boot problems, help plz =(

Im building my friends computer and its always going fine until you boot it up ; ). When I give the power supply power, the computer it POSTs up for a couple seconds and shuts back down. I dont have to hit the power button. The interesting thing is that If I hit restart every second, the computer stays up as long as it doesnt reach the (3?) second mark. Im running a P4 2.4 on P4T533-C w/ RDRAM. The RAM is installed correctly. If I install the reset button in the power button's jumper spot, it will turn on just fine but I get no video signal and the HD doesnt spool up. The ironic/insulting thing about it is that someone once brought me their computer because it was doing the same thing and I fixed it and I cant now. Any help would be great.

you said when you give the supply power... like when you plug it in or press the button (it is ATX right?)? if its when you plug it in i think your power switch is not pluged into the right spots or is mesed up- if thats nto it id make srue hte fan in plugged in and HS seated right

oh read the whol epost im lazy...i bet yoru power button is messed up as for no HD make sure you didnt make any stupid mistakes like not plugging it in lolz (iv done it) and for video make sure if its onboard plug it into there first then install the OS and after putting drivers olug it into the AGP/PCI card- you might have to disable onbard vid i fthis is the case

It was power button. Lotsa process of elimination. =) Thanks tho.