Pc build not powering on. Help Please

[tkh]

Just building a new computer for my grandad, it composes of:
Intel 4400 Core2Duo CPU Retail
Gbyte GA-965QM-DS2 Mobo
Corsair DDR2 TWINX 2GB PC6400
430W SEASONIC S12-430

Whenever I go to power it on, the fans spin for half a second, the power led lights up but then everything goes dead. Ive tried reseating the ram, reseating the cpu. Im out of ideas. Any help at all would be appretiated.

[Iain M]

checked that there's nothing shorting out the motherboard?

[Clunk]

A couple of possibles are..

The Seasonic doesnt like the Gigabyte board.

or

The board needs a bios update to see that cpu.

or

There is a short somewhere.

or

Try a different graphics card if possible.

or

Could be the board that is broke, but the PSU thing would be my first line of investigation.

[SiM]

I had that same problem before, twice - turned out that the early MSI neo2 platinum 939 motherboards like to kill themselves when put in the same case as an antec psu... Not sure why, the antec psu never made anything else die... The replacement MSI died in the same way too... I had to get a refund and buy the only other 939 board out at that time - the gigabyte one...

[ukengineer]

You connected the 4 pin power lead to the motherboard, normally near the cpu.

[tkh]

Yeah it seems to be that the psu isn't working with the motherboard, I havn't got another psu to try as im working on a laptop, but I have managed to get it to start once by moving the psu into a different position

[mcmiller]

Yeah it seems to be that the psu isn't working with the motherboard, I havn't got another psu to try as im working on a laptop, but I have managed to get it to start once by moving the psu into a different position

sounds like some sort of grounding issue, take the motherboard out of the case and try it

[tkh]

yeah the motherboard was always out of the case.

[IAmATeaf]

Could be a loose PSU to mobo power connector, try wiggling it around and if it boots then remove and inspect the connector.

[Clunk]

Some S12 PSUs have a problem at startup with some motherboards, usually Asus, so it does make sense. Good luck with the new PSU.

[d19z]

I've had this happen to a couple of my builds in the past, I had extra components lying around so I just played around until I outlined the cause, which in my case was the mobo, but it can be just as easily the fault of the PSU.