M2400: wont go onto bios or stay on for that matter

I bought a barebones M2400, came without Hdd,CPU ,Ram, Wifi. i installed all of these items and tried to fire it up and it wont boot. it powers on ,shows the splash page, back light on the keyboard comes on then it powers down. i re-seated the CPU 3-4 times to make sure it was installed properly( i have installed 100's so im sure that it is) i changed the ram and tested about 15 sticks of ram, i took the wifi card out, and i even tried 4 different Hdds. it does the same thing. the CPU works fine in my M17, and i am using it now. i tried all of the keys i know to get to a different screen, i tried f12 to get to the boot screen i tried f8,f2, it pauses then shuts down.

im at a loss, the seller is a really competent "computer"person on the fourms here, so i trust that he would have disassembled it properly, i also dissconnected the bios battery and did a power drain and still it does the same.

the only thing i can think of is that for some reason this MB willnot boot with an ES chip, i cant imagine that it would be able to detect the difference at POST and cause its self to power down, but i guess its possible, i dont know dells all that well.

anyone have an idea of what the issue may be?


thanks