self built pc wont turn on, please help

[hounddog]

okay i decided to build my own pc and bought some bits and pieces from ebay, heres what i bought..
Intel Pentium 4 D 930 (Dual core) LGA775, 3Ghz , 4mb 2 x 2Mb Cache, 800Mhz FSB.
ECS 649-M3 Motherboard (Micro atx)
gainward 7800gtx graphics card
1gb ddr2 memory
400watt psu
I built this machine up and it had no life in it at all apart from a funny noise that comes from the psu when i start it up (no fans or nothing at all) like it just trips out.
i figured this could be a memory or board problem so i went out and bought and new motherboard which is a ...
Asrock 775Dual-VSTA
so i rebuilt the machine and the same thing happens so i put in 1gb ddr memory from my current machine as this board can run either memory and still no joy
the funny thing is if i dont attach the 12v four pin onto the motherboard and just run it with the 20 pin attached then the board comes alive and the fans run but i dont get anything on screen and there are no beeps,
i have tried a friends 550watt psu to see if that was the problem but the same thing happens.
so now i'm left with the conclusion that maybe my processor is fried unless i'm doing something completely wrong here which i need you guys expertise on so please help me
(i knew i should have stuck with AMD)
(ive also tried building it outide of machine with only the 550watt psu and still the same problem)

[Tom]

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