Self built PC won't boot, help me please

[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)

(i have also tried building it outside of machine with only the psu connected and still same problem)

 

[PW_Ranger]

HMMMM... maybe here i can help u....MAYBE ur MB are spoil....

 

[hounddog]

well it's seems very strange that both motherboards could have exactly the same problem? i wish i had some some way of testing them before i go and buy a new cpu but ive always had amd products so i cant

 

[CrazeD]

EDIT: Never mind

Yeah it could be the CPU. RMA it, and see if a new one will work.

 

[hounddog]

ive had a bit of a breakthrough though coz ive just built it outside the case again (with old mobo) and the thing powered straight up and went to bios so i turned it off and on about 6 times and it started up every time, then i pulled it apart and put it back in the case and NOTHING grrr so ive built it back outside again and still nothing (the fans move for about a second then off) so now i know its not the cpu coz the bios picked it up correctly