computer not booting

[Missfitt5555]

Recently my power supply went out on my pc. I've bought a new one and also a new case while I was at it.I've been trying to get it to boot on two different motherboards. I tried it on my newer motherboard I bought 3 months ago and when I try to boot the fans will spin for 2 seconds and will shutdown, the power button seems to do nothing when I press it.to get a response out of it I have to replug the power supply to get any response. Similar things happen with the other board but I do not get as strong reaction from the fans with my order board.I had a friend test the ram in a known working pc. I feel as if I'm missing something really simple but I have no idea what it is.

 

[shivababbli]

i guess there might be some problem with your new psu, can u please give the complete details.
maybe if you have an electrometer you can check the voltage readings